Biblical Doctrine: A Systematic Summary of Bible Truth (God the Father: The Trinity)


Old Testament Indications

New Testament Evidence

Early History of Theological Development

The sense of God’s incomprehensibility is only heightened when the student of Scripture considers the reality that God is eternally triune. The classic Christian doctrine of the Trinity is well summarized by what is known as the Athanasian Creed. Though it bears his name, Athanasius (AD 295–373) did not write it; rather, it seems to have been penned in the fifth or sixth century AD at the earliest. The key defining statements are captured in this phrase: “We worship one God in Trinity, and Trinity in Unity; neither confounding the Persons: nor dividing the Substance.”39 The doctrine of the Trinity, simply put, is that God is absolutely and eternally one essence subsisting in three distinct and ordered persons without division and without replication of the essence.

Since the Trinity cannot be comprehended by the human mind, the doctrine of the Trinity must be defined with negative statements (often called “apophatic theology,” or “negative theology”). For example, the phrase “without division and without replication of the essence,” used above, is an expression of negative theology. Such phrases and assertions are needed to place proper boundaries on the positive statements, such as the one made above that “God is absolutely and eternally one essence subsisting in three distinct and ordered persons.” This positive statement needs boundaries to prevent people from thinking that the three persons each have either a third of the divine essence (partialism) or a full divine essence that is distinct from the full but identical essences of the other two persons (tritheism). If the essence were divided among the three persons, none of the persons would be divine. And if the essence were replicated in the three persons, the result would be three gods.

Though various historical heresies and contemporary cult groups accuse the Trinity of being an illogical doctrine derived from human philosophy, the triunity of God is neither of those things, because it is first and foremost a biblical doctrine. While it may be ultimately incomprehensible, it is not contrary to reason and logic but can be rationally explained, supported, and understood through biblical revelation. Berkhof elaborates:

The doctrine of the Trinity is very decidedly a doctrine of revelation. It is true that human reason may suggest some thoughts to substantiate the doctrine, and that men have sometimes on purely philosophical grounds abandoned the idea of a bare unity in God, and introduced the idea of living movement and self-distinction. And it is also true that Christian experience would seem to demand some such construction of the doctrine of God. At the same time it is a doctrine which we would not have known, nor have been able to maintain with any degree of confidence, on the basis of experience alone, and which is brought to our knowledge only by God’s special self-revelation. Therefore it is of the utmost importance that we gather the Scriptural proofs for it.



There is only one God, and he consists of one simple (uncompounded, indivisible) essence (Deut. 6:4; Mark 12:29; John 17:3; James 2:19; see “Unity: Numerical Oneness” and “Unity: Simplicity” above [p. 174]).


The one God exists eternally as three distinct persons (also known as subsistences and hypostases). The following passages reveal that there are three divine persons: Matthew 3:16–17; 4:1; John 1:18; 3:16; 5:20–22; 14:26; 15:26; 16:13–15. The distinctions between the persons is further specified by the following ancient illustration, variously referred to as “The Shield of the Trinity” or “The Shield of the Faith” (the earliest attestation dates to the early thirteenth century AD).41

       1.    The Father is God.

       2.    The Son is God.

       3.    The Holy Spirit is God.

       4.    The Father is not the Son.

       5.    The Father is not the Holy Spirit.

       6.    The Son is not the Holy Spirit.


Each person of the Trinity (also known as the Godhead) possesses the entire simple (undivided) essence of God. This fact means that the three persons, though distinct from one another, are coequal in every perfection of the divine essence. They are essentially coequal. That is, with respect to the essence of God, the three persons are equal to each other. Another way to say this is that the three persons are ontologically (with respect to their being or essence) equal to each other.


Because each of the three persons of the Trinity equally possess the full, undivided divine essence and are thus equally God, the question arises as to how these persons may be distinguished from one another. The best answer is to turn to Scripture itself and note that the most common way the persons of the Trinity are spoken of are as “Father,” “Son,” and “Holy Spirit.” These designations, also called the modes of subsistence, reveal the personal properties that distinguish each member of the Trinity from the others. By calling the first person of the Trinity “Father” (Lat. pater), Scripture intends to attribute the personal property of paternity to him with respect to the Son.

By calling the second person of the Trinity “Son” (Lat. filius), Scripture intends to attribute the personal property of filiation, or sonship, to him with respect to the Father. By calling the third person of the Trinity “Spirit” (Lat. spiritum), Scripture intends to attribute the personal property of spiration, or procession, to him with respect to the Father and the Son. By virtue of his paternity, the Father is unbegotten but eternally begets (or “generates,” Gk. gennaō) the Son. By virtue of his filiation, the Son is begotten, or eternally generated, by the Father. By virtue of his spiration, the Spirit eternally proceeds from both the Father and the Son. These concepts are best summarized by the Athanasian Creed:

The Father is made of none; neither created, nor begotten.

The Son is of the Father alone; not made, nor created; but begotten.

The Holy Ghost is of the Father and of the Son; neither made, nor created, nor begotten; but proceeding.

So there is one Father, not three Fathers; one Son, not three Sons; one Holy Ghost, not three Holy Ghosts.

These distinct modes of relationship establish a definite order (Lat. taxis) within the Trinity, so that it is proper to say (with respect to their relationship only, not with respect to their essence, glory, or majesty) that the Father is first, the Son is second, and the Spirit is third.

These acts of eternal generation and eternal procession are sometimes called the opera ad intra, or the internal works, of the Trinity. That is, they are eternal acts within the inner life of the Trinity, which establish the modes of personal subsistence of each member of the Godhead. They differ from the opera ad extra, or the external works, which produce effects outside God’s essence, that is, on the creation. Scripture ascribes God’s various works in the economy of redemption to a particular member of the Trinity. The Father is particularly singled out as the Creator (1 Pet. 4:19); the Son is distinguished as the Redeemer and Mediator (Rom. 3:24; Eph. 1:7; 1 Tim. 2:5); and the Spirit is identified as the agent of sanctification (2 Thess. 2:13; 1 Pet. 1:2). The external works of the Trinity in the economy of redemption therefore reflect the order established by the internal works of eternal generation and procession within the divine life. The Father sends the Son in the economy of redemption because he begets the Son eternally. The Spirit is sent by the Father and Son ad extra because he eternally proceeds from them ad intra.

Nevertheless, in all these works, all three persons of the Trinity work inseparably together (cf. John 14:10). Though one person or another may be emphasized in a particular work, no one person does any work exclusive of the other two persons, for, as the classic dictum states, “the external works of the Trinity are undivided” (opera Trinitatis ad extra indivisa sunt). Note, for example, the following passages, which ascribe the works outlined above to the other persons of the Trinity:

       1.    Creation and preservation

a.    Through the Son (John 1:3, 10; Col. 1:16–17; 1 Cor. 8:6; Heb. 1:2–3, 10)

b.    Through the Spirit (Gen. 1:2; Job 26:13; 32:8; 33:4; 34:14–15; Ps. 104:30)

       2.    Redemption

a.    Through the Father (1 Chron. 17:21; Isa. 63:16; Gal. 4:4–5)

b.    Through the Spirit (Heb. 9:14; Rom. 8:11)

       3.    Sanctification

a.    Through the Father (John 17:17; 1 Thess. 5:23)

b.    Through the Son (1 Cor. 1:30; Eph. 5:25–27)

A Mystery. The Trinity is a mystery in two senses. It is a mystery in the biblical sense in that it is a truth that was hidden until revealed. But it is also a mystery in that, in its essence, it is suprarational, ultimately beyond human comprehension. It is only partly intelligible to man, because God has revealed it in Scripture and in Jesus Christ. But it has no analogy in human experience, and its core elements (three coequal persons, each possessing the complete, simple divine essence, and each eternally relating to the other two without ontological subordination) transcend man’s reason.

Consequently, the doctrine must be accepted by faith, based on how the Godhead is revealed in Scripture. And it must be articulated in such a way that the essence of God is not divided and that the distinctions and the coequality of being between the three persons are not compromised. The doctrine of the Trinity needs both positive and negative theology.

Illustrations. The Trinity has no perfect analogies in human experience. Theologians have attempted to find a perfect illustration of the Trinity, but all these attempts have either divided the essence, compromised the distinction between the three persons, or lost sight of God’s personal essence. Nothing in the creation is exactly like the Trinity. What follows is a synthesis of these illustrations along with their weaknesses:

       1.    Illustrations from inanimate nature:

a.    Water of the fountain, creek, and river

b.    Rising mist, cloud, and rain

c.    Rain, snow, and ice

d.    Root, trunk, and branches of a tree

Weakness: The whole essence is not present but is divided or distributed.

       2.    Illustrations from man’s life and mind:

a.    Psychological unity of memory, affections, and will (Augustine’s analogy)

b.    Logical unity of thesis, antithesis, and synthesis (Hegel’s analogy)

c.    Metaphysical unity of subject, object, and subject-object (Shedd’s analogy)

Weakness: These lack any unity of the three.

       3.    Illustration from love: Necessitates subject, object, and union of the two

Weakness: Two persons (concretes) and a relationship (abstract) make up this triad, rather than three persons in the divine essence. Also, love is not a substance that is commonly possessed but a quality.

No illustration can fully communicate the Trinity, because the Trinity is God and always transcends the created order in essence, persons, and relationships. But as long as teachers make clear that every analogy will be to some extent inadequate, it may still be profitable to use these improper illustrations to explain why and how they fall short as adequate representations of the Trinity. By understanding that the Trinity is not like the three states of H2O (ice, water, vapor), the student learns to reject modalism. By learning that the Trinity is not like the three leaves of a single clover, he eschews partialism. By grasping that the Trinity is not like the light and heat emanating from the sun, he disclaims Arianism.

Old Testament Indications


The Hebrew divine name elohim, being a plural form, allows for a plurality in God. But the plural form does not necessitate this plurality, because there are reasons for using a plural other than indicating more than one entity (e.g., to show honor, or to denote intensity). Looking back from the clarity of the New Testament revelation, one can see elohim as at least a divine preparation for the later more complete revelation of God as triune.


In Ecclesiastes 12:1, “your Creator” translates a plural Hebrew participle, and in Isaiah 54:5, “your Maker” also translates a plural Hebrew participle. Again, because plurals have various possible uses in Hebrew, these titles do not prove that God is more than one person, although they are compatible with and prepare for the clearer New Testament revelation of the Trinity.


Further possible Old Testament evidence of God being more than one person is found in passages where God speaks of himself using other plural forms. In Genesis 1:26, God says, “Let us make man in our image.” The English verb with the plural pronoun translates a Hebrew first-person plural verb. God is speaking of himself and does not include the angels, because verse 27 says that “God created man in his own image.” Another Hebrew first-person plural verb refers to God speaking of himself in Genesis 11:7: “Come, let us go down and there confuse their language.” God is responding to man’s decision to erect the tower of Babel as an act of rebellion against the divine command to disperse themselves over the earth. There is no indication in Genesis 11 of anyone else but God in heaven.

In Genesis 3:22, God uses a plural pronoun to refer to himself: “Behold, the man has become like one of us.” In keeping with the Genesis 1:26 statement, Genesis 3:22 also refers only to God. Another plural pronoun is applied by God to himself in Isaiah 6:8, where God speaks so Isaiah can hear him: “Whom shall I send, and who will go for us?” Here the first-person singular Hebrew verb for God’s sending is followed by a plural pronoun referring to God.

These passages show God speaking of himself as both singular and plural. As with the name elohim, these plurals could be plurals of intensity. But the progressive clarity of the New Testament concerning the Trinity argues more that these plurals, considered in combination with singular verbs and pronouns for God, constitute God’s assertions that he is one and yet plural.


Yet stronger Old Testament evidence that God is more than one person comes in passages in which more than one person is called “God” or “Lord.” In Psalm 45:6–7, the Messiah is referred to as “God” (elohim) and is enthroned, having been anointed by “God” (elohim):

Your throne, O God, is forever and ever.

The scepter of your kingdom is a scepter of uprightness;

you have loved righteousness and hated wickedness.

Therefore God, your God, has anointed you

with the oil of gladness beyond your companions.

In Hebrews 1:8–9, by inspiration of the Holy Spirit, the author of Hebrews foretells that “God” will say the words of Psalm 45:6–7 to “the Son,” who will be enthroned as “God” by “God.”

Even more important is Psalm 110:1: “The Lord says to my Lord: ‘Sit at my right hand, until I make your enemies your footstool.’ ” In this messianic psalm—the Old Testament text most frequently quoted and alluded to in the New Testament—Yahweh speaks to the Messiah as “my Lord” (Heb. adonai). By inspiration, the New Testament writers identify Jesus as the “Lord” to whom the “Lord” speaks. Jesus himself implicitly asserted to the Pharisees that in this psalm David called the Messiah “Lord” (Matt. 22:41–45; Mark 12:35–37; Luke 20:41–44). Jesus was claiming to be divine, and David addressed him as such. In Acts 2:32–36, Peter said that Psalm 110:1 was fulfilled by the exaltation of Jesus after his resurrection.

The importance of these passages for Trinitarianism is that in the New Testament God the Holy Spirit asserted that Psalms 45:6–7 and 110:1 did reveal that there are at least two divine persons, and one of these is “the Son,” who is both elohim and adonai.


There are a few Old Testament passages that say that God has a “son.” Psalm 2:2, 6–7 predicts that God’s “Anointed” will be enthroned “on Zion” on the basis of God’s decree stating, “You are my Son; today I have begotten you.” So this “King” will be enthroned as God’s “Son” because of a decree naming him as God’s “Son.” Although in the Old Testament, Psalm 2:6–7 does not in and of itself assert that the one designated “my Son” is God’s eternal, divine Son, the Spirit-inspired New Testament applies this passage to Jesus as the eternal, divine Son (Heb. 1:1–3).


The Shema in Deuteronomy 6:4 states, “Hear, O Israel: The Lord our God, the Lord is one.” This Jewish creed, concerning Yahweh as the one true God and as only “one,” itself allows for a plurality in God as one. The word “one” in Deuteronomy 6:4 translates the Hebrew adjective ekhad, which affirms God’s unity but can allow for plurality in that unity. This word is also used in Genesis 2:24 of the “one flesh” of the husband and the wife in marriage. It is true that in other uses of ekhad, a compound unity is not meant. But if Deuteronomy 6:4 had been intended to assert that God is only one person, another Hebrew word would certainly have been used, namely, yakhid, which has the sense of “only, solitary” (see Ps. 68:6). Deuteronomy 6:4 is an affirmation of monotheism, not Unitarianism. It does not contradict the doctrine of the Trinity (see 1 Cor. 8:6) and even allows for God to be more than one person.


The Old Testament reveals this person as a divine person whom some passages refer to as Yahweh and God, and other passages depict as speaking to Yahweh. So the Old Testament presents the angel of Yahweh as Yahweh and yet also distinct from Yahweh.

Proofs that the angel of Yahweh was divine include the following:

       1.    His name was used interchangeably with God’s name (Gen. 16:7, 13; 21:17, 19–20; 22:11, 14; 31:11, 13; 48:15–16; Ex. 3:2, 4; Judg. 6:11, 14, 16, 20–21, 23; 13:3, 22–23).

       2.    When the angel of Yahweh made promises, God made them (Gen. 16:10; 22:15–17; cf. 12:2; 13:16).

       3.    Yahweh’s name was in the angel of Yahweh (Ex. 23:20–21).

       4.    People offered sacrifices to the angel of Yahweh (Gen. 22:11–13; Judg. 6:21; 13:16, 19–22).

       5.    As the predicted angel (“messenger”) of the covenant, he would be “the Lord” (Heb. adon, Mal. 3:1).

       6.    People who saw the angel of Yahweh identified him by name as divine (Gen. 16:11–13; Judg. 6:22–23; 13:21–22).

       7.    The angel of Yahweh could forgive sins (Ex. 23:21; Zech. 3:3–4).

       8.    The angel of Yahweh claimed to be “God” (Gen. 31:11, 13; Ex. 3:2–6).

What is especially important for Trinitarianism is that the Old Testament shows that the angel of Yahweh was called Yahweh and God but was also distinct from Yahweh:

       1.    Yahweh sent the angel of Yahweh (Ex. 23:20–23; 32:34; Num. 20:16).

       2.    The angel of Yahweh and Yahweh spoke to each other (Zech. 1:12–13).

The point of this section is that the Old Testament revelation of the angel of Yahweh is evidence that the Old Testament includes the truth that there is more than one person in the Godhead. It is little wonder that in light of the New Testament’s clearer revelation concerning the triunity of God, many theologians in church history (e.g., Justin Martyr, Irenaeus, Tertullian, Clement of Alexandria, Origen, Cyprian, Hilary of Poitiers, Basil of Caesarea, and John Calvin) have identified the Old Testament angel of Yahweh as the preincarnate Jesus Christ. They saw the Old Testament passages on the angel of Yahweh not as contradicting but as supporting the doctrine of the Trinity.


The Old Testament also speaks of the Holy Spirit as divine. Old Testament passages assert that the Holy Spirit has divine perfections. According to Isaiah 11:2, the Spirit is the source of divine wisdom, power, and knowledge, and Psalm 139:7 teaches that the Spirit is omnipresent. The Old Testament also depicts the Spirit as involved in the original act of creation and in the work of preserving what God has created (Gen. 1:2; Job 26:13; 34:14–15; Pss. 33:6; 104:30). The Spirit of God even restrains sin (Gen. 6:3; Isa. 63:10). Whatever the Holy Spirit is in Old Testament revelation, he is personal and divine. It might be argued that one cannot build a doctrine of the Spirit as a distinct, divine person from such Old Testament passages, and that such passages are no more than poetic representations of God’s presence. However, the Old Testament does not stand alone; the New Testament complements it with fuller revelation of the doctrine of the Trinity, including that the Holy Spirit is a distinct, divine person in the Godhead. Also, it should be noted that Jesus’s Jewish contemporaries, especially his disciples, seemed to understand that the Holy Spirit is a distinct, divine person (cf. Matt. 1:20; 3:11; Luke 1:15, 35; 11:13; 12:10; John 14:26; 20:22). Clearly, they either drew this concept from the Old Testament or at least saw it as fully consistent with it.


Another Old Testament aspect that prepares the way for the New Testament’s clearer revelation of the doctrine of the Trinity is the concept of God’s “word” (Heb. dabar). The New Testament revelation of the Son of God as the divine “word” is supported and foreshadowed by the following Old Testament truths:

       1.    God created by means of his word (Gen. 1:3, 6, 9, 11, 14, 20, 22, 24; Pss. 33:6, 9; 104:7; 147:18; 148:8).

       2.    God extends providential care by means of his word (Deut. 8:3; Pss. 106:9; 147:15–18).

       3.    God saves by means of his word: by his word, God gives life (Deut. 32:47; Ps. 119:25), guides (Ps. 119:105), chastens (Isa. 9:8), and will save the nation of Israel and restore the people to their land (Isa. 55:10–13).

       4.    God’s word has God’s power: God’s word breaks and cuts (Isa. 9:8–10), consumes like fire (Jer. 5:14), destroys like a hammer (Jer. 23:29), accomplishes God’s purpose (Isa. 55:11), and heals (Ps. 107:20).


There are at least three other Old Testament facets that serve as preparations for the New Testament doctrine of the Trinity.

Divine Wisdom. The Old Testament revelation of God’s wisdom is compatible with the New Testament teaching that God’s wisdom is a distinct, divine person, namely Christ. Thus, 1 Corinthians 1:24 calls Christ “the wisdom of God” (cf. 1 Cor. 1:30). In the Old Testament, God’s wisdom is his means of creating all things (Prov. 3:19). In Proverbs 8:22–36, God’s wisdom is poetically personified as God’s possession and as his means of giving life, instruction, and grace. Thus, passages like Proverbs 8 and Job 28:12–28 depict God’s wisdom as a distinct entity. Perhaps these passages describe wisdom as a person through poetic personification and therefore do not literally depict wisdom as a person. But the later apostolic revelation of Christ as “the wisdom of God” led many church fathers to see these passages as describing the preincarnate second person of the Trinity.

Three Distinct, Divine Entities. There are a few passages in Isaiah in which three distinct entities act. Isaiah 61:1–2 prophetically portrays the Messiah (“me”) saying,

The Spirit of the Lord God is upon me,

because the Lord has anointed me

to bring good news to the poor;

he has sent me to bind up the brokenhearted,

to proclaim liberty to the captives,

and the opening of the prison to those who are bound;

to proclaim the year of the Lord’s favor,

and the day of vengeance of our God;

to comfort all who mourn.

This passage contains “the Lord” (Yahweh), “the Spirit of the Lord,” and the speaker, who is the Messiah. The NKJV editors are correct in seeing the Messiah’s comments as starting in verse 1 and continuing through verse 9, which means that it is the Messiah who in verse 8 says, “I the Lord love justice.” In other words, the Messiah is sent by Yahweh and calls himself Yahweh. There are at least two divine persons in this passage, and because “the Spirit” is named, this context advances the preparation for the New Testament doctrine of the Trinity.

Another passage to consider is Isaiah 63:7–10:

I will recount the steadfast love of the Lord,

the praises of the Lord,

according to all that the Lord has granted us,

and the great goodness to the house of Israel

that he has granted them according to his compassion,

according to the abundance of his steadfast love.

For he said, “Surely they are my people,

children who will not deal falsely.”

And he became their Savior.

In all their affliction he was afflicted,

and the angel of his presence saved them;

in his love and in his pity he redeemed them;

he lifted them up and carried them all the days of old.

But they rebelled and grieved his Holy Spirit;

therefore he turned to be their enemy,

and himself fought against them.

Here, “the Lord” (Yahweh), “his Holy Spirit,” and “the angel of his presence” are mentioned. It seems best to see the latter as the angel of Yahweh discussed earlier. If that is so, then there are at least two divine persons in this context. And the Holy Spirit is here a person, because he is “grieved.” As such, the Holy Spirit is also divine, since it was the people’s grieving of him through rebellion that resulted in divine retribution. This passage moves further toward the full New Testament doctrine of the Trinity.

One more Old Testament passage that may specify three divine persons is Isaiah 48:12, 16:

“Listen to me, O Jacob,

and Israel, whom I called!

I am he; I am the first,

and I am the last.…

“Draw near to me, hear this:

from the beginning I have not spoken in secret,

from the time it came to be I have been there.”

And now the Lord God has sent me, and his Spirit.

There are at least two divine entities in this passage: “the Lord God” and “his Spirit” (Isa. 48:16). The personhood of the Spirit cannot be pressed immediately in this context, but when combined with Isaiah 63:7–10, it is clear that the Spirit is a divine person. But it is not absolutely clear if a third divine entity is depicted in Isaiah 48:12, 16. The English translations are divided over whether the speaker of verse 12, who is divine (“I am he; I am the first, and I am the last”), continues to speak to the end of verse 16. The NASB and NKJV hold that such is the case, which is the preferred view. In this translation, the Messiah is speaking; he is the “I am” and has been “sent” by “the Lord God” and “his Spirit.” In such a construction, the speaker and “the Lord God” are both divine persons, and “the Spirit” must also be divine, since the Spirit is seen by these translations as combining with “the Lord God” in sending the Messiah.

Emphasis on the Number Three. Finally, the Old Testament places an emphasis on the number three in various ways. These might have been divinely intended to prepare for the more explicit New Testament doctrine of the Trinity. Some of these emphases are threefold formulae, such as the seraphim praising Yahweh on his throne in heaven as “holy, holy, holy” (Isa. 6:3). Another example is the threefold Aaronic benediction in Numbers 6:24–27:

The Lord bless you and keep you;

the Lord make his face to shine upon you and be gracious to you;

the Lord lift up his countenance upon you and give you peace.

Peter Toon notes that the ancient church saw this threefold blessing as indicating the three persons of the Trinity, especially because the apostles were commanded to baptize in the “name” (singular) of the Trinity (Matt. 28:19). In Numbers 6:27, Yahweh said that this threefold blessing would be putting Yahweh’s “name” on the people of Israel.

Yet another threefold construction is Jacob’s threefold blessing of Joseph and his sons in Genesis 48:15–16:

And he blessed Joseph and said,

The God before whom my fathers Abraham and Isaac walked,

the God who has been my shepherd all my life long to this day,

the angel who has redeemed me from all evil, bless the boys;

and in them let my name be carried on, and the name of my fathers Abraham and Isaac;

and let them grow into a multitude in the midst of the earth.

In light of the previous discussion of the angel of Yahweh, it is well to note that Jacob says that “the angel” redeemed Jacob and would join with “God” in blessing Joseph’s sons. Since Jacob’s prayer had in view that only God could “bless” the boys, it is best to understand that “the angel” must be a distinct, divine person to bless jointly with God the Father.

Other emphases on the number three can be seen in the following passages: Genesis 15:9; 30:36; 40:10, 16; Exodus 3:18; 19:11; 23:14; Leviticus 19:23; Numbers 19:12; 22:23–41; 31:19; Jeremiah 7:4 (“the temple of the Lord” three times). Perhaps the use of three in ceremonial worship was meant to testify to Israel’s God being three yet one.

In light of the New Testament, the above aspects of the Old Testament progressively prepare for the New Testament’s clearer revelation of God as triune. Benjamin B. Warfield made a helpful elaboration of how the Old Testament more than prepared for the more complete New Testament revelation of the Trinity:

The upshot of it all is that it is very generally felt that, somehow, in the Old Testament development of the idea of God there is a suggestion that the Deity is not a simple monad, and that thus a preparation is made for the revelation of the Trinity yet to come. It would seem clear that we must recognize in the Old Testament doctrine of the relation of God to His revelation by the creative Word and the Spirit, at least the germ of the distinctions in the Godhead afterward fully made known in the Christian revelation. And we can scarcely stop there. After all is said, in the light of the later revelation, the Trinitarian interpretation remains the most natural one of the phenomena which the older writers frankly interpreted as intimations of the Trinity; especially of those connected with the descriptions of the Angel of Jehovah no doubt, but also even of such a form of expression as meets us in the “Let us make man in our image” of Gen. 1:26—for surely verse 27: “And God created man in his own image,” does not encourage us to take the preceding verse as announcing that man was to be created in the image of the angels. This is not an illegitimate reading of the New Testament ideas back into the text of the Old Testament; it is only reading the text of the Old Testament under the illumination of the New Testament revelation.… The mystery of the Trinity is not revealed in the Old Testament; but the mystery of the Trinity underlies the Old Testament revelation, and here and there almost comes into view. Thus the Old Testament revelation of God is not corrected by the fuller revelation which follows it, but only perfected, extended and enlarged.

New Testament Evidence

The New Testament is essential for a clear presentation of the doctrine of the Trinity. As discussed above, various Old Testament passages allow and even indicate that there is more than one divine person in God even though there is only one God. But the Old Testament assertions do not reveal enough details for believers to derive an explicitly Trinitarian doctrine of God. Such conclusive evidence is revealed in the New Testament. The church’s doctrine of the Trinity appeals to the Old Testament for inspired evidence, but it has always been based primarily on the progress of the whole of God’s revelation.


As shown previously in the section on the divine perfection of unity (p. 174), the Bible asserts that God is numerically only one. In the New Testament, Jesus repeats Deuteronomy 6:4 in Mark 12:29: “The Lord our God, the Lord is one.” In John 17:3, Jesus calls God the Father “the only true God.” Other passages also affirm monotheism: “God is one” (Rom. 3:30; James 2:19); “there is no God but one” (1 Cor. 8:4); and “there is one God” (1 Tim. 2:5). In Romans 3:30; 1 Corinthians 8:4; and 1 Timothy 2:5, “God” is God the Father, the first person of the Trinity, but as demonstrated below, the New Testament sometimes refers to God the Father as “God” to emphasize that he is God while depicting that the other two persons of the Trinity are also divine. The New Testament articulates that there is only one God but also refers to each of the three persons of the Trinity—the Father, the Son, and the Holy Spirit—as equally divine in names, nature, prerogatives, and works.


In some passages, the speaker or writer associates two persons with God. In John 5:17–18, Jesus claimed that he had the same authority to work on the Sabbath as “my Father.” Because of this statement, the Jewish religious leaders sought all the more to kill Jesus, because in their minds he had broken the Sabbath and “was even calling God his own Father, making himself equal with God” (John 5:18). In John 10:30, Jesus said, “I and the Father are one.” Because of that statement, the Jewish leaders picked up stones to stone him, accusing him of blasphemy, because by saying he was one with the Father, they believed that he was deifying himself: “You, being a man, make yourself God” (John 10:33). Jesus also said that he has everything that the Father has (John 16:15; 17:10). God the Father and Jesus Christ worked together in creating all things (1 Cor. 8:6), grace and peace come to believers from both God the Father and the Lord Jesus (1 Cor. 1:3; Eph. 1:2), and believers will reign on the earth with Christ for one thousand years as priests of both God the Father and Christ (Rev. 20:6).

Other passages associate all three persons of the Trinity with God. The Scriptures name the three persons equally and divinely in the following activities:

       1.    Eternally planning for and providing salvation to people (Eph. 1:3–14; 2:13–18; 1 Pet. 1:2)

       2.    Testifying to Jesus as the Son of God and the means of eternal life (1 John 5:1–12)

       3.    Publicly recognizing Jesus as the Savior of Israel (John 1:29–34)

       4.    Being present with and revealing truth to Jesus’s disciples (John 14:9–10, 26; 15:26; 16:7–15)

       5.    Giving faith, hope, and love in the hearts of believers (Col. 1:3–8)

       6.    Redeeming, justifying, and residing in believers (Gal. 3:11–14)

       7.    Bestowing spiritual gifts (1 Cor. 12:4–6)

       8.    Unifying the church (Eph. 4:4–6)

       9.    Continuing to bless believers (2 Cor. 13:14)

     10.    Securing believers in Christ (2 Cor. 1:20–22)

In the context of the New Testament, only God can provide what the Father, the Son, and the Holy Spirit are revealed as providing for the eternal salvation of believers in Christ.


The Father Is God. The New Testament specifies that each of the three persons of the Trinity are “God.” The name God (Gk. theos) combines with the name Father in many passages (e.g., John 6:27; Rom. 15:6; 1 Cor. 8:6; 15:24; Eph. 4:6; James 3:9). And as Murray Harris has demonstrated, when the name theos appears in the New Testament by itself in reference to the true God, it usually designates the first person of the Trinity, God the Father (e.g., James 1:5; 1 Pet. 3:18).

Jesus Is God. The New Testament also explicitly declares that Jesus is God. Jesus’s words claim that he is divine. He says that he is the Son of God (Matt. 26:63–64; Mark 14:61–62; Luke 22:67–71). He claims that he is the “I am” (Gk. ego eimi), thus bearing the Old Testament divine name of Yahweh. Many of these “I am” statements are connected with metaphors, such as “I am the bread of life” (John 6:35, 48), “I am the light of the world” (John 8:12), “I am the door” (John 10:9), “I am the good shepherd” (John 10:11, 14), and “I am the resurrection and the life” (John 11:25). But many of these statements are absolute, without any qualifiers (e.g., Mark 14:62; John 8:24, 28, 58; 13:19; 18:5–8). The absolute usage in John 13:19 occurs in the context of Jesus predicting that one of the disciples will betray him. He tells his disciples that he makes this statement so that “when it does take place you may believe that I am he.” The Greek words behind the English translation are taken from the Septuagint translation of Isaiah 43:10, which states, “in order that you may know and believe and understand that I am.” This statement appears in the larger context of Isaiah 40–48, in which God proves that he is the only true God, because only he can predict the future. So Jesus is saying that when his prediction that one of the disciples will betray him is fulfilled, it will prove that he is God.

Jesus also claims that the Father sent him, and so he came from heaven and had divine authority to do the works of the Father (John 3:13; 5:26–37; 6:31–58; 8:42; 16:28–30). And Jesus says that he has a special relationship with “my Father” that no one else has (e.g., Matt. 7:21; 10:32–33; 11:25–27; Luke 22:29; 24:49; John 2:16; 5:19–23; 8:36–38; 10:29–30, 36–38; 14:2–3, 11–12, 23; 15:8–10, 15; 16:10, 26–28; 17:1–26; 20:17).

John the Baptist says that Jesus is “the Lord” (John 1:15, 23, 30) and “the Son of God” (John 1:34). God the Father calls Jesus “my beloved Son” (Matt. 3:16–17; 17:5). Angels announce that Jesus is “the Son of God” (Luke 1:31–35) and “the Lord” (Luke 2:11)—in the latter passage, “Lord” is a divine name because it is a divine name in the near context (Luke 2:9, 15). In Matthew 14:33, the disciples worship Jesus as “the Son of God.” Peter confesses that Jesus is “the Son of the living God” (Matt. 16:16), and Thomas confesses that the risen Jesus is “my Lord and my God” (John 20:27–29). Before Jesus’s birth, he is called “Lord” by Elizabeth (Luke 1:43) and Zachariah (Luke 1:76). A centurion at the crucifixion affirms, “Truly this man was the Son of God!” (Mark 15:39).

Under the inspiration of the Holy Spirit, the New Testament writers say that Jesus is divine. Matthew says that Jesus is “God with us” (Matt. 1:23). Luke quotes Peter referring to Jesus as “Lord” in fulfillment of Psalm 110:1 (Acts 2:34–36) and also quotes Paul implying Jesus’s divinity by discussing “the church of God, which he obtained with his own blood” (Acts 20:28). Paul refers to Christ with the words “who is over all, the eternally blessed God” (Rom. 9:5 NKJV). Romans 10:9 and 1 Corinthians 12:3 say that the saving confession is “Jesus is Lord.” In Romans 14:8–9, Paul states that Christ is “Lord”—indeed, that he is “Lord both of the dead and of the living.” According to Paul, Jesus Christ is “the Lord of glory” (1 Cor. 2:8), and he is the “one Lord, Jesus Christ, through whom are all things and through whom we exist” (1 Cor. 8:6). Paul proclaims that Jesus existed “in the form of God” but “emptied himself, by taking the form of a servant” (Phil. 2:6–7). Paul goes on to say that Jesus humbled himself by becoming obedient to the point of death on the cross, that God the Father has “highly exalted” Jesus, and that one day all people will confess that “Jesus Christ is Lord” (Phil. 2:11). In Colossians 2:9, Paul asserts that in Jesus “the whole fullness of deity dwells bodily.”

A number of passages by the apostles name Jesus as “God” using a Greek grammatical construction for which grammarian Granville Sharp (1735–1813) articulated a rule (which now bears his name) and specified its relevance for the divine identity of Jesus Christ in the New Testament. The rule states that if the Greek conjunction kai joins two singular “nouns or participles” of personal description and of the same case, and if the Greek article ho precedes the first noun or participle but not the second, then “the latter … denotes a farther description” of the person described by the first noun or participle. Classic examples of the Granville Sharp construction are Titus 2:13 (“our great God and Savior Jesus Christ”), 2 Peter 1:1 (“our God and Savior Jesus Christ”), and 2 Peter 2:20 (“the Lord and Savior Jesus Christ,” NASB). According to Sharp, the construction in these passages means that Jesus is not only “Savior” but also “God” and “Lord.”

Yet another way in which the apostles identify Jesus as God is by referring to Jesus with Old Testament passages that refer to Yahweh. In John 12:36–41, by inspiration of the Holy Spirit, John quoted Isaiah 53:1 and Isaiah 6:10 as reasons why the Jews “did not believe in” Jesus even though “he had done so many signs before them” (John 12:37). John says that this unbelief fulfills the two Old Testament passages he quoted. John concludes in John 12:41 that “Isaiah said these things because he saw his glory and spoke of him.” The antecedent of “his” and “him” in this verse is the “he” of verse 37, which refers to “Jesus” in verse 36. Thus, John identifies Jesus as the “Lord” (Heb. adonai) of Isaiah 6:1, whom Isaiah saw “sitting upon a throne,” and the “Lord [Yahweh] of hosts” of Isaiah 6:3, whose “glory” fills “the whole earth.” So Jesus is the “Lord” and “Lord” of Isaiah 6:1–3.

Other New Testament passages also refer to Jesus by using Old Testament passages referring to Yahweh. Acts 2:21 and Romans 10:13 quote Joel 2:32 to indicate that the phrase “calls on the name of the Lord” (Yahweh in Joel 2:32) means believing and confessing that Jesus is Lord. Hebrews 1:10–12 asserts that God “says” the words of Psalm 102:25–27 “to the Son” (Heb. 1:8), thus indicating that Jesus is the “God” (Heb. el) and the “Lord” (Yahweh) of Psalm 102. And Ephesians 4:7–8 uses the words of Psalm 68:18 to express that when Christ ascended, he gave gifts to his church. But the Old Testament passage refers to God ascending to his “mount” (Ps. 68:16) and “receiving gifts” (Ps. 68:18). So in citing Ephesians 4:7–8, Paul means that Christ was divine in his ascension and was authorized to distribute gifts to the church.

The Holy Spirit Is God. The New Testament also identifies the Holy Spirit as divine. His titles associate him with the other persons of the Trinity: “Spirit of God” (Matt. 3:16); “Spirit of the Lord” (Luke 4:18); “Spirit of your Father” (Matt. 10:20); “my Spirit” (Acts 2:17–18); “Spirit of Christ” (Rom. 8:9); “the Lord, the Spirit” (2 Cor. 3:17–18 NASB).

There are other even more explicit assertions that the Holy Spirit is God. In Acts 5:3–4, 9, Peter says that in lying to the Holy Spirit, Ananias and Sapphira had “not lied to man but to God.” In 2 Corinthians 3:17–18, Paul declares, “The Lord is the Spirit,” and refers to the Spirit as “the Lord, the Spirit” (NASB). Paul also says in 1 Corinthians 3:16 that “God’s Spirit” indwells the church, because the church is “God’s temple.” And in Ephesians 2:22, Paul states that it is “by the Spirit” that the church is “being built together into a dwelling place for God.”

Furthermore, the New Testament claims that the Holy Spirit spoke the words of Old Testament passages, words that those passages declare come directly from God. In Acts 28:25–27, Paul says that the Holy Spirit spoke “through Isaiah” the words of Isaiah 6:9–10, even though in Isaiah 6, it was “the voice of the Lord” who said these words (Isa. 6:8). The same correspondence between words of New Testament passages and Old Testament passages is visible in the following couplets: Hebrews 3:7–11 with Psalm 95:7–11; Hebrews 10:15–17 with Jeremiah 31:31–34.


The New Testament depicts each person of the Trinity as having characteristics that are divine perfections. These characteristics are divine because the New Testament asserts them to be standards by which characteristics of other beings are measured. God the Father is powerful (Matt. 19:26), omnipresent (Matt. 6:4, 6), omniscient (Matt. 6:4, 6, 8; Luke 16:15), true (John 3:33), righteous (John 17:25; cf. Acts 10:34), and living (Matt. 26:63; John 5:26; 6:57).

God the Son, incarnate as Jesus Christ, is eternal (John 1:1; 8:58; 17:5; Rev. 1:8; 21:6; 22:13), omniscient (John 1:47–48; 2:24–25; 16:30; 21:17; Rev. 2:23), omnipresent (Matt. 18:20; 28:20; John 1:48–50), omnipotent (Matt. 8:26–27; 9:25; 21:19; 28:18; Mark 5:11–15; Luke 4:38–41; 7:14–15; John 2:11; 5:36; 10:25, 38; 11:43–44; Heb. 1:3; Rev. 1:8), immutable (Heb. 1:10–12; 13:8), loving (Eph. 5:2), holy (Luke 1:35; John 8:46; Heb. 7:26–27; 1 John 3:5), life (1 John 1:2; 5:20), and truth (John 14:6).

God the Holy Spirit is eternal (Heb. 9:14), holy (Eph. 4:30), omniscient (John 14:26; 16:12–13; 1 Cor. 2:10–11), omnipotent (Luke 1:35, 37; 1 Cor. 12:11; Rom. 15:19), glory (1 Pet. 4:14), life (Rom. 8:2), truth (John 14:17; 15:26; 16:13; 1 John 4:6), and grace (Heb. 10:29).


According to the New Testament, each person of the Trinity has divine prerogatives. These are divine because the Bible ascribes them as if they are rights that no other beings have. God the Father has the right to receive worship (John 4:23; James 3:9), give commands (John 14:31), forgive sin (Matt. 6:14), and judge (John 5:30). God the Son has the right to receive worship (Matt. 14:33; 28:9; John 20:28; Heb. 1:6), give commands (John 15:12, 14), forgive sin (Mark 2:8–12), judge (Matt. 25:31–32; John 5:22; Acts 10:42; 17:31; Rom. 14:10–11; 2 Cor. 5:10; 2 Tim. 4:1; 1 Pet. 4:1, 5; Rev. 19:11–15; 22:12–13), and be the object of faith (John 1:12; 20:31). God the Holy Spirit has the right to receive worship (Eph. 4:30; 1 Thess. 5:19; Heb. 10:29), know the deep things of God (1 Cor. 2:10), give commands (Acts 8:29; 10:19–20), and bestow gifts (1 Cor. 12:4, 7–8, 11).


The New Testament specifies that each person of the Trinity performs divine acts. These are divine because the New Testament asserts that they determine all other reality. God the Father creates (1 Cor. 8:6), sustains life (Matt. 6:26), reveals truth (Matt. 16:17; Heb. 1:1–2), raises the dead (Rom. 6:4), and judges (Matt. 15:13; Acts 17:31). God the Son creates (John 1:3, 10; 1 Cor. 8:6; Eph. 3:9; Col. 1:16; Heb. 1:2), sustains all things (Col. 1:17; Heb. 1:3), reveals truth (John 16:12–13), raises the dead (John 5:28–29; 10:17–18), and judges (John 5:22, 27; Acts 10:42; 2 Tim. 4:1). God the Holy Spirit creates (Gen. 1:2; Job 26:13; Ps. 33:6), reveals truth and inspires its writing (John 16:13; 1 Cor. 2:12–13; 2 Pet. 1:21), raises the dead (Rom. 8:11), regenerates (John 3:5–6; Titus 3:5), indwells (2 Tim. 1:14), secures by sealing (Eph. 1:13–14), gives God’s love (Rom. 5:5), and guides (Rom. 8:14).


As mentioned previously, there are eternal relations between the persons of the Trinity: the Father, the Son of God, and the Spirit of God. The Father eternally begets the Son and eternally spirates the Holy Spirit. The Son is eternally begotten of the Father and eternally spirates the Holy Spirit. The Spirit eternally proceeds from the Father and the Son.

The eternal generation of the Son and the eternal procession of the Spirit are two of the most misunderstood doctrines of classic Trinitarianism, because there are no suitable analogies in the human realm that can be used to explain or illustrate the terminology. Although Scripture expressly speaks of the Father’s begetting the Son (Ps. 2:7) and the Spirit’s proceeding from the Father (John 15:26), the Bible gives no clear and complete explanation of what those expressions mean. Indeed, begetting and breathing are creaturely activities, so the language alone is clearly inadequate to express the full wonder and glory of the inner relationships within the eternal, immutable, ineffable Godhead. The words must therefore be understood (as best we can) in light of everything Scripture says about the Father, the Son, and the Holy Spirit. (This section is to be read in concert with the earlier section “Personal Distinctions” [p. 191]).

At first glance, eternal generation seems oxymoronic. In normal human discourse, the words generate and beget speak of bringing someone or something into existence. In the human realm, begetting occurs only once, at a definite point in time. To pair the idea with the adjective eternal is to change it in the most radical way. And it is absolutely vital to understand and affirm the difference between the begetting of a human child and the eternal generation of the Son of God. When we say Christ is eternally begotten of the Father, we are not talking about his beginning, for Scripture plainly says, “He was in the beginning with God. All things were made through him, and without him was not any thing made that was made” (John 1:2–3). There never was a time when the Son did not exist. He is “the Alpha and the Omega, the first and the last, the beginning and the end” (Rev. 22:13).

How, then, can Christ be eternally begotten of the Father? The answer is surprisingly simple. When terms like begetting or generation are used to speak of the heavenly Father’s relation to his Son (e.g., Ps. 2:7; cf. Acts 13:33; Heb. 1:5; 5:5), what those words describe is not his beginning (for he had none) but the establishment from all eternity of the filial relationship between the first and second persons of the Trinity. The expression thus describes the eternal, necessary, and self-differentiating act of God the Father by which he generates the personal subsistence of the Son and thereby communicates to the Son the entire divine essence (cf. John 5:26).

This relationship is unique; it is the very thing that distinguishes the Son from the Father and the Spirit. In other words, the Spirit is not begotten; his mode of subsistence is procession. Similar to eternal generation, the procession of the Spirit from the Father and the Son describes the eternal, necessary, and self-differentiating act of the Father and the Son by which they spirate the personal subsistence of the Spirit and thereby communicate to him the entire divine essence. Scripture does not explicitly define the difference between generation and procession, but the terminology befits the names Son and Spirit. Begetting has the connotation of filiation (i.e., that which is proper to sonship), and procession is a suitable expression to pair with the concepts of spirit or breath. Clearly, the distinction between begetting and proceeding is purposeful and important, even if we cannot fully explain how the two modes of subsistence differ from one another.

It is well known that the Eastern church split from the Western church over the question of whether the Holy Spirit proceeds from the Father only or from the Father and the Son (Lat. filioque). In John 15:26, Jesus says, “The Spirit of truth … proceeds from the Father.” And in John 20:22, in one of his early postresurrection appearances to the disciples, it states that “he breathed on them and said to them, ‘Receive the Holy Spirit’ ”—symbolizing the very idea suggested by the language used to speak of the Spirit’s procession. So we affirm—with the rest of the Western church—that the Holy Spirit proceeds from the Father and the Son. The Athanasian Creed (Quicunque Vult) states the relations within the Godhead in the most succinct language possible: “The Father is made of none; neither created, nor begotten. The Son is of the Father alone; not made, nor created; but begotten. The Holy Ghost is of the Father and of the Son; neither made, nor created, nor begotten; but proceeding.”

As mentioned earlier, these opera ad intra establish a definite order (Lat. taxis) within the Trinity, so that it is proper to say (with respect to their relationship only, not with respect to their essence, glory, or majesty) that the Father is first, the Son is second, and the Spirit is third. The ad intra works of eternal generation and procession become the ground for the order reflected in the ad extra works in the economy of redemption. The Son submits to the Father in the economy of redemption (cf. John 5:30; 6:38) because he was eternally generated by the Father. The Spirit is sent by the Father and the Son (cf. John 14:26; 15:26) because he eternally proceeds from the Father and the Son. Yet none of this implies a rank or hierarchy of essence within the Trinity, for each person fully possesses the undivided divine essence. The Athanasian Creed likewise sums up the clear teaching of Scripture in a remarkable economy of words: “And in this Trinity none is afore, or after another; none is greater, or less than another. But the whole three Persons are coeternal, and coequal. So that in all things, as aforesaid: the Unity in Trinity, and the Trinity in Unity, is to be worshiped.”

Early History of Theological Development

As a conclusion to the study of the Trinity, it is important to briefly observe how the doctrine of the Trinity was (1) observed in Scripture and (2) articulated by the ancient church. The word Trinity and other technical terms (e.g., person, essence) in the traditional orthodox doctrine of the Trinity are not found in Scripture yet are based on biblical verbiage. The doctrine of the Trinity was formally articulated by the Councils of Nicaea (AD 325) and Constantinople (AD 381), but these councils did not invent the doctrine; rather, they set forth a dogma (official proclamation) to counter prevailing heresies. In post–New Testament church history, the affirmation of the doctrine goes back to the expressions of the early apostolic fathers (ca. AD 90–150). These men—such as Clement of Rome (fl. ca. 88–99), Polycarp (ca. 69–155), and Ignatius (ca. 50–ca. 110)—affirmed the deity of the Father, the Son, and the Holy Spirit without speculating about their relations with each other. During this period, the church began to experience Roman persecution, and some of the apostolic fathers died as martyrs. The church also began to deal with the Gnostic heresy.

The next period of the ancient church (AD 150–300) witnessed increasing Roman persecution and fresh heresies, in addition to the spread of Gnosticism. Gnosticism was monistic and dualistic, denying real distinctions in reality and treating matter and flesh as inherently evil, not created by God, who was protected from matter by a series of emanations. Gnostics denied the incarnation of Christ since they believed that God would never join with matter nor come to earth, and they produced their own spurious books, including false gospels.

Other heresies from this period included various forms of Monarchianism (an early Unitarianism). Dynamic (Adoptionistic) Monarchianism taught that the Father alone is God and that Jesus was just a man who was indwelt by an impersonal divine force (the Logos) either at his birth, his baptism, or his resurrection. He had a delegated divinity through this indwelling divine power, and his divinity was limited to this power only and featured no divine essence.

Modalistic Monarchianism (Modalism, Sabellianism, and Patripassianism) taught that the Father and the Son are one and the same. God is called Father or Son according to the figure of the times. Born of a virgin, he is called Son; to those who believed in him, he revealed that he was the Father. The one God was metamorphosed in external form according to the need of the moment. In other words, there is only one God who presents himself in various forms (Father, Son, or Spirit) as he wishes. In this heresy, these forms are modes of manifestation, not modes of being.

Church leaders in this period—such as Justin Martyr (ca. 100–165), Irenaeus (ca. 120–202), Tertullian (ca. 160–ca. 220), Clement of Alexandria (ca. 150–ca. 215), and Origen (ca. 184–ca. 254)—began to write more extensively as apologists and theologians to counter the false charges that pagans leveled against Christians and to oppose Gnosticism and Monarchianism. These men greatly advanced the orthodox explanation of Trinitarian doctrine. Irenaeus wrote five books against Gnosticism. His writings were more detailed concerning the relations of the Father, the Son, and the Holy Spirit. Tertullian coined the Latin word trinitas for the Godhead and the Latin word persona for the persons. Origen affirmed the eternal deity of the Son and identified the three persons by the Greek word hypostasis and the one essence by the Greek word ousia. All the apologists affirmed the divine essence and distinct personhood of each member of the Trinity.

One problem that occurred as the apologists wrote about the Trinity was a growing ontological subordinationism. Justin, Irenaeus, and Tertullian started to write about the generation of the Son as if it were an eternal production. Origen went even further, saying that the Son was a “secondary God,” inferior to the Father.

Origen’s thinking about the Father and the Son helped pave the way for the teachings of Arius (250–336) in Alexandria to gain some acceptance—even though Arius subordinated the Son in ways that Origen never did. Arius taught that Jesus was only a man into whom the Logos came. The Logos, the Son, was the highest and first creation of God. So the Son was not God but a creature.

Theological contemplation and explanation advanced in the next period (300–600) as peace finally came to the church, making it possible for the church to deal with the Arian heresy, as well as other Christological heresies. The Roman persecutions climaxed with an empire-wide persecution under Emperor Diocletian in the early fourth century. The persecutions ended under Emperor Constantine, who had a zeal for promoting the church. With the end of persecutions also came the advance of Arianism and doctrinal division in the church. In 325, Constantine called the first ecumenical council, the Council of Nicaea, to restore unity. Through the influence of Athanasius, secretary and future successor to Alexander, the bishop of Alexandria, the council issued a creed affirming that the Son is “very God of very God” and “of one substance” (homoousios) with the Father. However, there were many factions at the council, including Arians, and each had its own interpretation of the Greek word homoousios. For the next fifty years, semantic and theological conflict continued. The Macedonian heresy, derived from Arianism, argued that the Holy Spirit was also a created being. Gradually the Alexandrian view of the relationships of the Father, the Son, and the Holy Spirit prevailed as Greek and Latin churchmen discussed and agreed on common Trinitarian language. At the Council of Constantinople (381), the Nicene formula was reasserted and expanded. The majority knew that it was affirming the full and equal deity of both the Son and the Spirit as evidenced by the fact that this council specified that the Holy Spirit is “the Lord and Giver of life” and is to be “worshiped and glorified” equally with the Father and the Son.

In subsequent years, orthodox churches assumed the viewpoint of Nicaea and Constantinople, accepting the doctrine of these councils because it reflected what they already believed. Between 399 and 419, Augustine of Hippo wrote an extensive volume on the Trinity to further explain and defend orthodox Trinitarianism in the Latin-speaking churches. The Western churches made one formal change to the Creed of Constantinople at the Synod of Toledo in 589. The Latin word filioque (“and the Son”) was added at the end of the expression that the Holy Spirit “proceeds from the Father” to indicate that the Holy Spirit also proceeds from the Son. The Greek-speaking Eastern churches resisted this revision to the creed because they believed that it changed the creed without the approval of the whole church and put the Son on the same plane as the Father as a “cause” of the Trinity. The Western churches instituted the change in the Niceno-Constantinopolitan Creed because they wanted to emphasize (against Arianism) the eternal, divine equality of the Son with the Father. The disagreement over this change was a major factor leading to the permanent division of the Eastern church from the Western church in 1054.

What is important to understand is that in the midst of the imperial and ecclesiastical politics of 300–500, the basic motivation behind the church leaders’ aim to more clearly explain the doctrine of the Trinity was that they interpret Scripture correctly. Testifying to the influence of Scripture is the fact that the Greek wording of the Nicene Creed was based on the Greek language of 1 Corinthians 8:6, which was the focus of much conflict between the Arian and orthodox bishops. The explanation of the doctrine of the Trinity developed ultimately because these theologians disagreed over the meaning of the Bible. Later on, the major Reformers reaffirmed the wording of what has become known as the Niceno-Constantinopolitan Creed. The Reformation became a revival of belief in the Bible and of the study of it in the original languages. The Reformers would never have affirmed the Niceno-Constantinopolitan Trinitarian doctrine unless they believed that it agreed with Scripture, a sentiment captured in this statement by Martin Luther (1483–1546): “Scripture thus clearly proves that there are three Persons and one God. For I would believe neither the writings of Augustine nor the teachers of the Church unless the New and Old Testaments would clearly show this doctrine of the Trinity.”[1]

[1] MacArthur, J., & Mayhue, R., eds. (2017). Biblical Doctrine: A Systematic Summary of Bible Truth (pp. 189–210). Crossway.