For I will be merciful to their iniquities, and I will remember their sins no more. (8:12)
Here is the capstone of the New Covenant. Here is what men need more than anything else—and what the Old Covenant pictured but could not give. The promise of the Old Testament is finally fulfilled! Under the Old Covenant, sins could never really be forgotten, because they were never really forgiven. They were only covered, foreshadowing and anticipating true forgiveness in Jesus Christ. But for those who belong to His dear Son—whether they believed under the Old Covenant or under the New—God forgets every sin.
12. For, &c.—the third of “the better promises” (Heb 8:6). The forgiveness of sins is, and will be, the root of this new state of inward grace and knowledge of the Lord. Sin being abolished, sinners obtain grace.
I will be merciful—Greek, “propitious”; the Hebrew, “salach,” is always used of God only in relation to men.
and their iniquities—not found in Vulgate, Syriac, Coptic, and one oldest Greek manuscript; but most oldest manuscripts have the words (compare Heb 10:17).
remember no more—Contrast the law, Heb 10:3.
12. For I will forgive their wickedness
and will remember their sins no more.”
The description of the new covenant is positive; the stipulations are not implied but clearly stated in the form of four promises (8:6).
For the third time in this lengthy quotation Jeremiah writes “declares the Lord.” God himself makes the new covenant with the people who belong to the messianic age. That is, Jew and Gentile as believers make up “the house of Israel.” The era of the old covenant, characterized by the exclusiveness of the nation Israel, has made way for a new age in which all nations are included (Matt. 28:19).
Who belongs to the house of Israel? All those people, says God, in whose minds I will put my laws and upon whose hearts I will write them. The expressions minds and hearts (parallel terms) represent man’s inner being. God’s people experience the permeating power of God’s Word, so that his law becomes a part of their conscience. That conscience is directed to the law of God, much the same as a compass needle invariably points north.
Throughout Scripture God’s recurring message to his people is the promise: “I will be their God, and they will be my people” (see, for example, Exod. 6:7; Lev. 26:12; Jer. 7:23; 11:4; 2 Cor. 6:16; Rev. 21:3). God wanted to make the Israelite nation his special people; they were his “treasured possession.” However, Israel could lose this favored status if the people refused to keep the law of God. The covenant stipulated that God’s people would live a life of obedience.
In New Testament times, too, God addresses the believers in Jesus Christ and gives them the covenant promise: “I will be [your] God, and [you] will be my people.” In this new covenant, God is inseparably united with his people because God’s law has been inscribed on their hearts. He communicates with his people through his revelation, and they communicate with him through prayer. He encourages them to approach the throne of grace with confidence (Heb. 4:16), and he makes it known that his name has been written on their foreheads (Rev. 14:1; 22:4). He wants to have them address him as Father, for they are his children.
Ye children of God’s covenant,
Who of His grace have heard,
Forget not all His wondrous deeds
And judgments of His word.
The Lord our God is God alone,
All lands His judgments know;
His promise He remembers still,
While generations go.
The next promise flows from the preceding promises. The knowledge of the Lord shall be universal. In the history of Israel, God’s revelation came piecemeal “through the prophets at many times and in various ways” (Heb. 1:1), and in one instance the Book of the Law was discovered in the temple of the Lord. While the Book of the Law gathered dust, the people lived in ignorance (2 Kings 22; 2 Chron. 34:14–28). Ignorance of God’s revelation was appalling, and God’s prophets repeatedly registered their complaints (see Isa. 1:3; Jer. 4:22; Hos. 4:6).
What a difference in New Testament times! Knowledge of the Lord will be universal, covering the earth “as the waters cover the sea” (Isa. 11:9; Hab. 2:14). The need for individual teaching—“a man teach his neighbor, or a man his brother,” “from the least of them to the greatest”—will disappear because all people will know the Lord. Filled with the knowledge of the Lord, even novices in the faith are able and equipped to witness for him. All those who have the law of God in their hearts and minds acknowledge God’s grace and mercy. They know that their sins have been forgiven and that their record has been wiped clean.
When God forgives sin, he does so by never remembering man’s sin again. That means that when forgiven, man is like Adam and Eve in Paradise: without sin. Man, forgiven by God, is accepted as if he had never sinned at all. God says, “I will remember [his] sins no more.” In the new covenant, grace and mercy are freely given to all God’s children. God gives these blessings in the name of his Son, who is the mediator of a new covenant. This new covenant established through the death of Jesus on the cross is the believer’s guarantee that his sins are forgiven and forgotten.
8:12. God had promised new power to fulfill his laws and a new closeness to know and understand him. His third promise offered forgiveness to sinners. A literal translation of verse 12 has God promising, “I will be merciful to their deeds of unrighteousness.” God had always been merciful. The new covenant gave more open expression to God’s mercy.
The parallel statement that God would remember their sins no more reassured sinners that God’s forgiveness was complete. God, unlike human beings, does not say, “I will forgive, but I will not forget.” God promises to forget our sins.
The ground of forgiveness was not human repentance but Jesus’ sacrificial death. Only the death of Jesus could provide full assurance that God has wiped away sins and made believers righteous in his sight. God took the initiative to give sinners his grace and mercy. Because God really dealt with sins, the blessings of knowing him and serving him with power become possible.
 MacArthur, J. F., Jr. (1983). Hebrews (p. 216). Chicago: Moody Press.
 Jamieson, R., Fausset, A. R., & Brown, D. (1997). Commentary Critical and Explanatory on the Whole Bible (Vol. 2, p. 460). Oak Harbor, WA: Logos Research Systems, Inc.
 Kistemaker, S. J., & Hendriksen, W. (1953–2001). Exposition of Hebrews (Vol. 15, pp. 226–227). Grand Rapids: Baker Book House.
 Lea, T. D. (1999). Hebrews, James (Vol. 10, p. 156). Nashville, TN: Broadman & Holman Publishers.