Salt of the Earth and Light of the World
You are the salt of the earth; but if the salt has become tasteless, how will it be made salty again? It is good for nothing anymore, except to be thrown out and trampled under foot by men. You are the light of the world. A city set on a hill cannot be hidden. Nor do men light a lamp, and put it under the peck-measure, but on the lampstand; and it gives light to all who are in the house. Let your light shine before men in such a way that they may see your good works, and glorify your Father who is in heaven. (5:13–16)
In these four verses the Lord summarizes the function of believers in the world. Reduced to one word, that function is influence. Whoever lives according to the Beatitudes is going to function in the world as salt and light. Christian character consciously or unconsciously affects other people for better or for worse. As John Donne reminds us, “No man is an island.”
An ancient Greek myth tells of a goddess who came to earth unseen but whose presence was always known by the blessings she left behind in her pathway. Trees burned by forest fires sprouted new leaves, and violets sprang up in her footprints. As she passed a stagnant pool its water became fresh, and parched fields turned green as she walked through them. Hills and valleys blossomed with new life and beauty wherever she went. Another Greek story tells of a princess sent as a present to a king. She was as beautiful as Aphrodite and her breath was as sweet as perfume. But she carried with her the contagion of death and decay. From infancy she had fed on nothing but poison and became so permeated with it that she poisoned the very atmosphere around her. Her breath would kill a swarm of insects; she would pick a flower and it would wither. A bird flying too close would fall dead at her feet.
Andrew Murray lived an exceptionally holy life. Among those on whom his influence was the greatest were his children and grandchildren. Five of his six sons became ministers of the gospel and four of his daughters became minister’s wives. Ten grandsons became ministers and thirteen grandchildren became missionaries.
Woodrow Wilson told the story of being in a barbershop one time. “I was sitting in a barber chair when I became aware that a powerful personality had entered the room. A man had come quietly in upon the same errand as myself to have his hair cut and sat in the chair next to me. Every word the man uttered, though it was not in the least didactic, showed a personal interest in the man who was serving him. And before I got through with what was being done to me I was aware I had attended an evangelistic service, because Mr. D. L. Moody was in that chair. I purposely lingered in the room after he had left and noted the singular affect that his visit had brought upon the barber shop. They talked in undertones. They did not know his name, but they knew something had elevated their thoughts, and I felt that I left that place as I should have left a place of worship.”
Many years ago Elihu Burrit wrote, “No human being can come into this world without increasing or diminishing the sum total of human happiness, not only of the present but of every subsequent age of humanity. No one can detach himself from this connection. There in no sequestered spot in the universe, no dark niche along the disc of nonexistence to which he can retreat from his relations with others, where he can withdraw the influence of his existence upon the moral destiny of the world. Everywhere his presence or absence will be felt. Everywhere he will have companions who will be better or worse because of him. It is an old saying, and one of the fearful and fathomless statements of import, that we are forming characters for eternity. Forming characters? Whose? Our own or others? Both. And in that momentous fact lies the peril and responsibility of our existence. Who is sufficient for the thought? Thousands of my fellow beings will yearly enter eternity with characters differing from those they would have carried thither had I never lived. The sunlight of that world will reveal my finger marks in their primary formations and in their successive strata of thought and life.”
In Matthew 5:13–16 Jesus talks about the influence of His people on the world for God and for good. In His high priestly prayer Jesus said to His Father, “I do not ask Thee to take them out of the world, but to keep them from the evil one. They are not of the world, even as I am not of the world.… As Thou didst send Me into the world, I also have sent them into the world” (John 17:15–16, 18). John wrote, “Do not love the world, nor the things in the world” (1 John 2:15). Christ’s kingdom people are not to reflect the world but they are to influence the world; they are to be in it but not of it.
When we live the life of the Beatitudes some people will respond favorably and be saved, whereas others will ridicule and persecute us. In the words of Paul, we will manifest “the sweet aroma of the knowledge of [Christ] in every place. For we are a fragrance of Christ to God among those who are being saved and among those who are perishing; to the one an aroma from death to death, to the other an aroma from life to life” (2 Cor. 2:14–16). In either case our lives have profound effects, and even persecution is not to alter our function in the world. We “are a chosen race, a royal priesthood, a holy nation, a people for God’s own possession, that [we] may proclaim the excellencies of Him who has called [us] out of darkness into His marvelous light” (1 Pet. 2:9).
Though Jesus was speaking before a great multitude of people on the hillside, His teaching about kingdom life was primarily for His disciples, for those who believed in Him. His concern was for the all of the multitude, and in hearing His teaching on godly living many of them may have been drawn to faith. But the principles He teaches here are appropriate only for believers, for they are impossible to follow apart from the power of God’s own Spirit.
Here is a mandate for Christians to influence the world. The Beatitudes are not to be lived in isolation or only among fellow believers, but everywhere we go. God’s only witnesses are His children, and the world has no other way of knowing of Him except through the testimony of what we are.
The figures of salt and light emphasize different characteristics of influence, but their basic purpose is the same. They will both be studied from the aspects of the presupposition of the world’s corruption and darkness, the plan for believers’ godly dominion in the world, the problem of the danger of failure, and the purpose of glorifying God.
The Presupposition: Corruption and Darkness
The world needs salt because it is corrupt and it needs light because it is dark. G. Campbell Morgan said, “Jesus, looking out over the multitudes of His day, saw the corruption, the disintegration of life at every point, its breakup, its spoliation; and, because of His love of the multitudes, He knew the thing that they needed most was salt in order that the corruption should be arrested. He saw them also wrapped in gloom, sitting in darkness, groping amid mists and fogs. He knew that they needed, above everything else, … light” (The Gospel According to Matthew [New York: Revell, 1929], p. 46).
The biblical world view is that the world is corrupted and decayed, that it is dark and darkening. “Evil men and impostors will proceed from bad to worse, deceiving and being deceived,” Paul warns (2 Tim. 3:13). The world cannot do anything but get worse, because it has no inherent goodness to build on, no inherent spiritual and moral life in which it can grow. Year after year the system of evil accumulates a deeper darkness.
A college student told me his professor had recently told the class that marriage was on the decline because man was evolving to a higher level. Marriage was something that man needed only at the lower stages of his evolutionary development. Now that man had ascended farther up the evolutionary scale, marriage was falling off just as his prehensile tail had done millions of years ago.
Any person who knows the history of mankind, even the history of the past hundred years, and thinks that man is evolving upward is “deceiving and being deceived,” just as Paul said. Man has increased in scientific, medical, historical, educational, psychological, and technological knowledge to an astounding degree. But he has not changed his own basic nature and he has not improved society. Man’s knowledge has greatly improved, but his morals have progressively degenerated. His confidence has increased, but his peace of mind has diminished. His accomplishments have increased, but his sense of purpose and meaning have all but disappeared. Instead of improving the moral and spiritual quality of his life, man’s discoveries and accomplishments have simply provided ways for him to express and promote his depravity faster and more destructively. Modern man has simply invented more ways to corrupt and destroy himself.
Many philosophers, poets, and religious leaders at the end of the last century had great optimism about man’s having come of age, about his inevitable moral and social improvement. They believed that Utopia was around the corner and that man was getting better and better in every way. The golden age of mankind was near. Wars would be a bad memory, crime and violence would disappear, ignorance would be gone, and disease would be eradicated. Peace and brotherhood would reign completely and universally. Few people today hold to such blind, unrealistic ideas.
It was not many generations after the Fall that “the Lord saw that the wickedness of man was great on the earth, and that every intent of the thoughts of his heart was only evil continually” (Gen. 6:5). Because wickedness was so great, God destroyed every person but eight—and they were far from perfect. A few generations after that, the cities of Sodom and Gomorrah became so rotten from the offspring of those eight that God destroyed them with fire and brimstone. Another day of judgment is coming when God will again rain fire on earth, but that destruction will be a holocaust such as men have never dreamed of. “The present heavens and earth by His word are being reserved for fire, kept for the day of judgment and destruction of ungodly men … the heavens will pass away with a roar and the elements will be destroyed with intense heat, and the earth and its works will be burned up” (2 Pet. 3:7, 10).
Man is infected with the deadly virus of sin, which has no cure apart from God. Yet unlike their attitude toward physical diseases, most men do not want their sin cured. They love their decadence and they hate God’s righteousness (cf. John 3:19–21). They love their own way and they hate God’s.
Man’s knowledge is increasing by quantum leaps, but his increased knowledge is mechanical knowledge, inanimate knowledge, lifeless knowledge, knowledge that has no bearing on the inner man (cf. 2 Tim. 3:7). His knowledge does not retard his corruption but rather is used to intensify and defend it.
Bertrand Russell devoted most of his 96 years to the study of philosophy. Yet at the end of his life he acknowledged that philosophy proved to be a washout, and had taken him nowhere. Nothing he had thought or had heard that other philosophers had thought had changed the world for the better. He felt that the basic causes of man’s problems, not to mention the solutions, had evaded the best minds of every age including his own.
Some scientists have proposed that by surgery or careful electronic stimulation of the brain, a person’s bad impulses can be eradicated, leaving only the better part of his nature. Others propose that the ideal, crime-free, problem-free person will be developed by genetic engineering. But every part of every man is corrupt. He has no inherent, naturally good traits that can be isolated from the bad. His total nature is depraved. David knew that he was sinful from the moment of his conception. “Behold, I was brought forth in iniquity, and in sin my mother conceived me” (Ps. 51:5). There is no good part in man from which a better can be constructed or from which his corrupt part can be isolated. Isaiah said, “The whole head is sick, and the whole heart is faint” (Isa. 1:5), and Jeremiah labeled the heart as “more deceitful than all else” and as “desperately sick” (Jer. 17:9).
We go on from war to greater war, from crime to greater crime, from immorality to greater immorality, from perversion to greater perversion. The spiral is downward, not upward (see Rom. 1:18–32). Despair and pessimism reign in our day, because the honest person knows that man has not been able to retard his descent. He hopes that he can just live out his own life before someone pushes the button that blows mankind into oblivion.
A leading news magazine reported a few years ago that Americans tend to see themselves as potential saints rather than real-life sinners. Another leading magazine reported, “Today’s young radicals in particular are almost painfully sensitive to … wrongs of their society, and they denounce them violently. But at the same time they are typically American in that they fail to place evil in its historic and human perspective. To them evil is not an irreducible component of man; it is not an inescapable fact of life, but something committed by the older generation, attributable to a particular class or the establishment and eradicable through love or revolution” (Time, 5 December 1969).
Just as every person is affected by the sin problem, every person also contributes to the sin problem.
The Plan: The Dominion of His Disciples
The church cannot accept the world’s self-centeredness, easy solutions, immorality, amorality, and materialism. We are called to minister to the world while being separated from its standards and ways. Sadly, however, the church today is more influenced by the world than the world is influenced by the church.
In both verse 13 and verse 14 the pronoun you is emphatic. The idea is, “You are the only salt of the earth” and “You are the only light of the world.” The world’s corruption will not be retarded and its darkness will not be illumined unless God’s people are its salt and light. The very ones who are despised by the world and persecuted by the world are the world’s only hope.
The you in both verses is also plural. It is His whole body, the church, that is called to be the world’s salt and light. Each grain of salt has its limited influence, but it is only as the church collectively is scattered in the world that change will come. One ray of light will accomplish little, but when joined with other rays a great light is created.
Some years ago a magazine carried a series of pictures that graphically depicted a tragic story. The first picture was of a vast wheat field in western Kansas. The second showed a distressed mother sitting in a farmhouse in the center of the field of wheat. The accompanying story explained that her four-year-old son had wandered away from the house and into the field when she was not looking. The mother and father looked and looked all day but the little fellow was too short to see or be seen over the wheat. The third picture showed dozens of friends and neighbors who had heard of the boy’s plight and who had joined hands the next morning to make a long human chain as they walked through the field searching. The final picture was of the heartbroken father holding his lifeless son who had been found too late and had died of exposure. The caption underneath read, “O God, if only we had joined hands sooner.”
The world is full of lost souls who cannot see their way above the distractions and barriers of the world and cannot find their way to the Father’s house until Christians join together as salt and light and sweep through the world in search of them. Our work is not simply as individual grains of salt or as individual rays of light but as the whole church of Jesus Christ.
Are stresses being rather than doing. Jesus is stating a fact, not giving a command or request. Salt and light represent what Christians are. The only question, as Jesus goes on to say, is whether or not we are tasteful salt and effective light. The very fact that we belong to Jesus Christ makes us His salt and light in the world.
Christ is the source of our savor and of our light. He is “the true light which, coming into the world, enlightens every man” (John 1:9). “While I am in the world, I am the light of the world,” He said (John 9:5). But now that He has left the world His light comes to the world through those whom He has enlightened. We shine forth the reflected light of Christ. “You were formerly darkness, but now you are light in the Lord,” Paul tells us; “walk as children of light” (Eph. 5:8). “For He delivered us from the domain of darkness, and transferred us to the kingdom of His beloved Son” (Col. 1:13).
We are God’s salt to retard corruption and His light to reveal truth. One function is negative, the other positive. One is silent, the other is verbal. By the indirect influence of the way we live we retard corruption, and by the direct influence of what we say we manifest light.
Both salt and light are unlike that which they are to influence. God has changed us from being part of the corrupted and corrupting world to being salt that can help preserve it. He has changed us from our own darkness to be His agents of giving light to others. By definition, an influence must be different from that which it influences, and Christians therefore must be different from the world they are called to influence. We cannot influence the world for God when we are worldly ourselves. We cannot give light to the world if we revert to places and ways of darkness ourselves.
The great blessings emphasized in verses 3–12 lead to the great responsibilities of verses 13–16. The blessings of heaven, comfort, inheriting the earth, being filled with righteousness, being given mercy, being called God’s children, and being given heavenly reward bring the responsibility of being His salt and light in the world.
Salt has always been valuable in human society, often much more so than it is today. During a period of ancient Greek history it was called theon, which means divine. The Romans held that, except for the sun, nothing was more valuable than salt. Often Roman soldiers were paid in salt, and it was from that practice that the expression “not worth his salt” originated.
In many ancient societies salt was used as a mark of friendship. For two persons to share salt indicated a mutual responsibility to look after one another’s welfare. Even if a worst enemy ate salt with you, you were obliged to treat him as a friend.
Salt was frequently used in the ancient Near East to bind a covenant, somewhat in the way an agreement or contract is notarized in our day. When the parties to a covenant ate salt together before witnesses, the covenant was given special authentication. Though no particulars are given in the account, we learn from 2 Chronicles 13:5 that God made a covenant of salt with David. God prescribed that all sacrificial offerings in Israel were to be offered with salt “so that the salt of the covenant of your God shall not be lacking” (Lev. 2:13).
In numerous ways Jesus’ hearers—whether Greek, Roman, or Jewish—would have understood salt of the earth to represent a valuable commodity. Though most could not have understood His full meaning, they knew He was saying that His followers were to have an extremely important function in the world. Whatever else it may have represented, salt always stood for that which was of high value and importance.
Many suggestions have been made as to the particular characteristics of salt that Jesus intended to associate with this figure. Some interpreters point out that salt is white and therefore represents purity. As the “pure in heart” (v. 8), Jesus’ disciples are to be pure before the world and are to be God’s means of helping purify the rest of the world. Their glistening white moral and spiritual purity is to contrast with the moral discolor of the world. Christians are to exemplify the divine standards of righteousness in thought, speech, and actions, remaining “unstained by the world” (James 1:27). All that is certainly true; but it does not seem to the point, because saltiness, not the color of salt, is the issue.
Others emphasize the characteristic of flavor. That is, Christians are to add divine flavor to the world. Just as many foods are tasteless without salt, the world is drab and tasteless without the presence of Christians. Someone has even said, “We Christians have no business being boring. Our function is to add flavor and excitement to the world.” Christians are a means of God’s blessing mankind, including unbelievers, just as He sends His sun and rain on the righteous and unrighteous alike.
There are certain senses in which that principle is true. An unbelieving marriage partner is sanctified by a believing spouse (1 Cor. 7:14), and God offered to spare Sodom for the sake of only ten righteous people, if that many could be found within it (Gen. 18:32).
The problem with that view, however, is that, from the earliest days of the church, the world has considered Christianity to be anything but attractive and “flavorful.” It has, in fact, often found the most spiritual Christians to be the most unpalatable. In the world’s eyes, Christians, almost above all others, take the flavor out of life. Christianity is stifling, restrictive, and a rain on the world’s parade.
After Christianity became a recognized religion of the Roman Empire, the emperor Julian lamented, “Have you looked at these Christians closely? Hollow-eyed, pale-cheeked, flat-breasted, they brood their lives away unspurred by ambition. The sun shines for them, but they don’t see it. The earth offers them its fullness, but they desire it not. All their desire is to renounce and suffer that they may come to die.”
Oliver Wendell Holmes reportedly once said that he might have entered the ministry if certain clergymen he knew had not looked and acted so much like undertakers. Sometimes the world is turned away from the church because Christians are hypocritical, self-righteous, judgmental, and truly boring by any standard. But even when the church is faithful—indeed, especially when it is faithful—the world does not value whatever taste or aroma it sees in Christianity. Paul reminds us that Christians are an “aroma from life to life” and “a fragrance of Christ to God among those who are being saved,” but are an “aroma of death to death” among “those who are perishing” (2 Cor. 2:15–16).
Because salt stings when placed in a wound, some interpreters believe that Jesus meant to illustrate just the opposite characteristic to that of flavor. Christians are to sting the world, prick its conscience, make it uncomfortable in the presence of God’s holy gospel.
That analogy also has merit. The church frequently is so concerned with trying to please, attract, and excuse that its witness against sin is obscured and all but lost. We may be so concerned with not offending others that we fail to confront them with their lostness and their desperate need to be saved from their sin. A gospel that does not confront sin is not the gospel of Jesus Christ.
Some years ago a young couple who came to me to be married said they knew the Lord had brought them together and given them to each other. The woman claimed to have been a Christian all her life, but her concept of salvation was that of trying to please God by doing the best she could. She admitted that, although she had filed for divorce because her husband had been unfaithful, she was still married to him. On further questioning, she admitted that she had been committing fornication with the young man she now wanted to marry. The young man claimed to be born again, but he saw no great wrong in their relationship and no reason why they should not be married in a Christian service. I told them that God could not possibly have brought them together because they were living contrary to His revealed will—and worse, trying to justify it. At that point they both got up and angrily stormed out of the office.
The church cannot stand for the Lord if it does not stand for His Word, and when it stands for His Word its witness will often sting.
Salt also creates thirst. Partly because it increases the body’s craving for water, salt tablets often are given to those who do hard work in excessive heat. Without proper intake of fluids, dehydration and even death may result. God intends for His people so to live and testify before the world that others will be made more aware of their spiritual dehydration and danger. A person may see our peace in a trying circumstance, or our confidence in what we believe, and thereby be persuaded to try our faith.
I believe that all of the foregoing analogies have some validity. Christians are to be pure; they should add a certain attractiveness to the gospel; they should be true to God’s Word even when it stings; and their living should create a thirst for God in those who do not know Him.
But I believe the primary characteristic Jesus emphasizes is that of preservation. Christians are a preserving influence in the world; they retard moral and spiritual spoilage. When the church is taken out of the world at the rapture, Satan’s perverse and wicked power will be unleashed in an unprecedented way (see 2 Thess. 2:7–12). Evil will go wild and demons will be almost unbridled. Once God’s people are removed it will take only seven years for the world to descend to the very pits of hellishness (see Dan. 9:27; Rev. 6–19).
Until that day Christians can have a powerful influence on the welfare of the world. Martyn Lloyd-Jones writes, “Most competent historians are agreed in saying that what undoubtedly saved [England] from a revolution such as that experienced in France at the end of the eighteenth century was nothing but the Evangelical Revival. This was not because anything was done directly, but because masses of individuals had become Christians and were living this better life and had this higher outlook. The whole political situation was affected, and the great Acts of Parliament which were passed in the last century were mostly due to the fact that there were such large numbers of individual Christians found in the land” (Studies in the Sermon on the Mount [Grand Rapids: Eerdmans, 1971], 1:157).
As God’s children and as the temples of His Holy Spirit, Christians represent God’s presence in the earth. We are the salt that prevents the entire earth from degenerating even faster than it is.
Helen Ewing was saved as a young girl in Scotland and gave her life completely to the lordship of Christ. When she died at the age of 22 it is said that all Scotland wept. She had expected to serve God as a missionary in Europe and had become fluent in the Russian language. But she was not able to fulfill that dream. She had no obvious gifts such as speaking or writing, and she had never traveled far from home. Yet by the time she died she had won hundreds of people to Jesus Christ. Countless missionaries mourned her death because they knew that a great channel of their spiritual strength was gone. She had risen every morning at five in order to study God’s Word and to pray. Her diary revealed that she regularly prayed for over three hundred missionaries by name. Everywhere she went the atmosphere was changed. If someone was telling a dirty story, he would stop if he saw her coming. If people were complaining, they would become ashamed of it in her presence. An acquaintance reported that while she was at Glasgow University she left the fragrance of Christ wherever she went. In everything she said and did she was God’s salt.
Jesus also calls us to be light. You are the light of the world. Whereas salt is hidden, light is obvious. Salt works secretly, while light works openly. Salt works from within, light from without. Salt is more the indirect influence of the gospel, while light is more its direct communication. Salt works primarily through our living, while light works primarily through what we teach and preach. Salt is largely negative. It can retard corruption, but it cannot change corruption into incorruption. Light is more positive. It not only reveals what is wrong and false but helps produce what is righteous and true.
In his introduction to the book of Acts, Luke refers to his gospel as “the first account I composed, Theophilus, about all that Jesus began to do and teach” (1:1). Christ’s work always has to do with both doing and speaking, with living and teaching.
David wrote, “For with Thee is the fountain of life; in Thy light we see light” (Ps. 36:9). “God is light,” John reminds us, “and in Him there is no darkness at all. If we say that we have fellowship with Him and yet walk in the darkness, we lie and do not practice the truth; but if we walk in the light as He Himself is in the light, we have fellowship with one another, and the blood of Jesus His Son cleanses us from all sin” (1 John 1:5–7). Light is not given simply to have but to live by. “Thy word is a lamp to my feet, and a light to my path,” the psalmist tells us (Ps. 119:105). God’s light is to walk by and to live by. In its fullest sense, God’s light is the full revelation of His Word—the written Word of Scripture and the living Word of Jesus Christ.
God’s people are to proclaim God’s light in a world engulfed in darkness, just as their Lord came “to shine upon those who sit in darkness and the shadow of death” (Luke 1:79). Christ is the true light, and we are His reflections. He is the Sun, and we are His moons. A free rendering of 2 Corinthians 4:6 could be, “God, who first ordered the light to shine in the darkness has flooded our hearts with His light. We now can enlighten men only because we can give them knowledge of the glory of God as we have seen it in the face of Jesus Christ.” God sheds His light on the world through those who have received His light through Jesus Christ.
The Jews had long claimed to have God’s light, and He had long called them to be His light. But because they had ignored and rejected His light, they could not be His light. They were confident that they were guides “to the blind, a light to those who are in darkness,” but Paul told them they were blind guides and lamps without light. “You, therefore, who teach another, do you not teach yourself?” he asks (Rom. 2:19–21). They had the light, but they were not living by it. “You who preach that one should not steal, do you steal?” Paul continues by way of illustration. “You who say that one should not commit adultery, do you commit adultery?” (vv. 21–22). We are to prove ourselves “to be blameless and innocent, children of God above reproach in the midst of a crooked and perverse generation, among whom [we are to] appear as lights in the world” (Phil. 2:15).
By its nature and by definition light must be visible in order to illuminate. Christians must be more than the largely indirect influence of salt; they must also be the direct and noticeable instruments of light.
Both in the daytime and at night, a city set on a hill cannot be hidden. It is exposed for all to see. By day its houses and buildings stand out on the landscape, and at night the many lights shining out of its windows make it impossible to miss. A secret Christian is as incongruous as a hidden light. Lights are to illuminate, not to be hidden; to be displayed, not to be covered. Christians are to be both subtle salt and conspicuous light.
God did not give the gospel of His Son to be the secret, hidden treasure of a few but to enlighten every person (John 1:9). Many reject the light and reject those who bring it, but just as God offers His light to the whole world, so must His church. It is not our gospel but God’s, and He gives it to us not only for our own sakes but the entire world’s. True believers are salt and light, and must fulfill that identity.
The Problem: Danger of Failure
but if the salt has become tasteless, how will it be made salty again? It is good for nothing anymore, except to be thrown out and trampled under foot by men. (5:13b)
Much salt in Palestine, such as that found on the shores of the Dead Sea, is contaminated with gypsum and other minerals that make it taste flat and even repulsive. When a batch of such contaminated salt would find its way into a household and be discovered, it was thrown out. People would be careful not to throw it on a garden or field, because it would kill whatever was planted. Instead it would be thrown onto a path or road, where it would gradually be ground into the dirt and disappear.
There is a sense in which salt cannot really become unsalty. But contamination can cause it to lose its value as salt. Its saltiness can no longer function.
Jesus is not speaking of losing salvation. God does not allow any of His own to be taken from Him. “My sheep hear My voice, and I know them, and they follow Me; and I give eternal life to them, and they shall never perish; and no one shall snatch them out of My hand,” Jesus assures us (John 10:27). Christians cannot lose their salvation, just as salt cannot lose its inherent saltiness. But Christians can lose their value and effectiveness in the kingdom when sin and worldliness contaminate their lives, just as salt can become tasteless when contaminated by other minerals. It is a common New Testament truth that although true believers are identified as righteous, godly, and salty, there are times when they fail to be what they are (cf. Rom. 7:15–25), which Peter says leads to loss of assurance (2 Pet. 1:9–10), not loss of salvation.
With great responsibility there is often great danger. We cannot be an influence for purity in the world if we have compromised our own purity. We cannot sting the world’s conscience if we continually go against our own. We cannot stimulate thirst for righteousness if we have lost our own. We cannot be used of God to retard the corruption of sin in the world if our own lives become corrupted by sin. To lose our saltiness is not to lose our salvation, but it is to lose our effectiveness and to become disqualified for service (see 1 Cor. 9:27).
Pure salt does not lose its saltiness, that which makes it valuable and effective. Christians who are pure in heart do not become tasteless, ineffective, and useless in the kingdom of God.
Light, too, is in danger of becoming useless. Like salt, it cannot lose its essential nature. A hidden light is still light, but it is useless light. That is why people do not light a lamp, and put it under the peck-measure, but on a lampstand; and it gives light to all who are in the house. The exemplary woman praised in Proverbs 31 does not let her lamp go out at night (v. 18). There was always illumination for anyone in the household who had to get up or find his way home during the night. A light that is hidden under a peck-sized basket cannot even be used to read by; it helps neither the person who hides it nor anyone else.
Whether we hide our light because of fear of offending others, because of indifference and lovelessness, or because of anything else, we demonstrate unfaithfulness to the Lord.
The Purpose: to Glorify God
Let your light shine before men in such a way that they may see your good works, and glorify your Father who is in heaven. (5:16)
The word (kalos) for good that Jesus uses here does not so much emphasize quality—though that obviously is important—as it does attractiveness, beautiful appearance. Letting our light shine before men allows them to see our good works, the beauty the Lord has worked in us. To see good works by us is to see Christ in us. That is why Jesus says, let your light shine. It is not something we create or make up, but something we allow the Lord to do through us. It is God’s light; our choice is whether to hide it or let it shine.
The purpose of letting our light shine and reveal our good works is not to bring attention or praise to ourselves but to God. Our intent should be that, in what we are and in what we do, others may see God in order that they may glorify [our] Father who is in heaven. Jesus’ speaking of the Father emphasizes God’s tenderness and intimacy, and speaking of His being in heaven emphasizes His majesty and holiness, as He is pictured dwelling in the splendor of His eternal holy home. Our good works are to magnify God’s grace and power. This is the supreme calling of life: glorifying God. Everything we do is to cause others to give praise to the God who is the source of all that is good. The way we live should lead those around us to glorify (doxazō, from which we get doxology) the heavenly Father.
When what we do causes people to be attracted to us rather than to God, to see our human character rather than His divine character, we can be sure that what they see is not His light.
It is said of Robert Murray McCheyne, a godly Scottish minister of the last century, that his face carried such a hallowed expression that people were known to fall on their knees and accept Jesus Christ as Savior when they looked at him. Others were so attracted by the self-giving beauty and holiness of his life that they found his Master irresistible.
It was also said of the French pietist Francois Fenelon that his communion with God was such that his face shined with divine radiance. A religious skeptic who was compelled to spend the night in an inn with Fenelon, hurried away the next morning, saying, “If I spend another night with that man I’ll be a Christian in spite of myself.”
That is the kind of salt and light God wants His kingdom people to be.
The Light of the World
When Jesus Christ described the proper function of his disciples in this world in the Sermon on the Mount he made use of two sublime illustrations. The first was salt. He said, “You are the salt of the earth.” We already have studied that illustration. The second illustration is light. Jesus said, “You are the light of the world. A city on a hill cannot be hidden. Neither do people light a lamp and put it under a bowl. Instead they put it on its stand, and it gives light to everyone in the house. In the same way, let your light shine before men, that they may see your good deeds and praise your Father in heaven” (Matt. 5:14–16).
We need to look at these words carefully, for they are profound. They teach important lessons about the nature of Christ and this world, the imperatives and strengths of the Christian life, and the obligation of a believer to remain in close fellowship with his Lord.
A Darkened World
The first clear implication of Christ’s words is that the world is in darkness where spiritual things are concerned. And the tragedy of the situation is that men actually prefer the darkness to God’s light. Several years ago an old woman in the bush country of southern Rhodesia said to a missionary, “You missionaries have brought us the light, but we don’t seem to want it. You have brought us the light, but we still walk in darkness.” She was speaking only of the life she knew in Africa. But her words aptly describe the reaction of all men to the light of Christ and to the Christian gospel. Jesus was the light of the world when he was in the world. Today, Christians are the light of the world. The tragedy is that men actually prefer the darkness. That is, they prefer their own imperfect and sinful way of doing things instead of the perfect and holy standards of Jesus Christ.
Part of the problem, of course, is that most men will not admit this. A few years ago a national news magazine made some accurate remarks about the presence of sin and evil in America and the reaction of Americans to it, but they could have been even more accurate if the words had been extended to the world in general. The magazine wrote, “It is the particular heresy of Americans that they see themselves as potential saints more than as real-life sinners.” And it added in reference to the young radicals of our society, “Today’s young radicals, in particular, are almost painfully sensitive to these and other wrongs of their society, and denounce them violently. But at the same time they are typically American in that they fail to place evil in its historic and human perspective. To them, evil is not an irreducible component of man, an inescapable fact of life, but something committed by the older generation, attributable to a particular class or the ‘Establishment,’ and eradicable through love and revolution” (Time, Dec. 5, 1969, p. 27). Unfortunately, evil is an irreducible component of man, and it is no less real because most men are unwilling to acknowledge it.
It was the particular achievement of Jesus Christ that he exposed the nature of the darkness in a way that had never been done previously. And, of course, men hated him for it. One commentator has written, “The light which reveals the world does not make the darkness, but it makes the darkness felt. If the sun is hidden, all is shadow, though we call that shadow only which is contrasted with the sunlight; for the contrast seems to intensify that which is however left just what it is before. And this is what Christ has done by His coming. He stands before the world in perfect purity, and we feel as men could not feel before He came, the imperfection, the impurity of the world. The line of separation is drawn forever, and the conscience of men acknowledges that it is rightly drawn. Whether we know it or not the light which streams from Christ is ever opening the way to a clearer distinction between good and evil. His coming is a judgment. The light and the darkness are not blended in him, as they are in us, so that opinion can be doubtful.”
Actually, the coming of Jesus into the world exposed the world’s darkness, even where men thought they had most light. When I was very young I spent a number of summers at a Christian camp in Canada. Each summer my friends and I took several camping trips. The trips were fun, as I remember, but the sleeping accommodation was not. The ground was hard. Often it was damp. Generally there were rocks underneath the bedding. I remember lying awake sometimes for most of the night talking or fooling around with the other campers. During a particularly long night we would play with our flashlights. We would shine them in one another’s eyes, and the game was to see which light was the brightest. Generally, the flashlight with the brightest reflector or the largest number of batteries won. Now, obviously, the game could be played only in the dark. For eventually the sun came up, and after that the differences between the flashlights faded into insignificance by comparison.
That is what happened when the Lord Jesus Christ came into the world, and that is what men and women still experience today when they come face to face with him. As long as we live in the darkness and are never exposed to God’s light you and I are able to compare the relative merits of human goodness and be totally oblivious to how much in darkness we are. We are able to see the difference between a three-battery character, a two-battery character, and one that has almost gone out. We rate men accordingly. Fortunately, all these distinctions fade away in the presence of the white light of the righteousness of Jesus Christ. For his coming and his presence reveal the depth of the darkness of your character and mine.
What is your reaction to that? It can be one of two things. You can hate Christ for it, as many people have done, and attempt to get rid of his presence in your life. (When Jesus was on earth, those who felt that way crucified him.) Or you can do what he wants you to do. You can say, “Lord, I see now that my own works are far from perfect. If they seem bright to me, it is only because I am measuring them by my own low standard. I realize that they will never take me to heaven. I ask you to give me that goodness which I do not have, as you have promised to do, and remove my sin forever. I believe in you and your work of redemption.” And Jesus will do that. He is as good as his word. The Bible says, “God made him [Jesus Christ] who had no sin to be sin for us, so that in him we might become the righteousness of God” (2 Cor. 5:21).
“You Are the Light”
At this point you may be saying to yourself something like this: “Dr. Boice, you began by quoting Christ’s statement that Christians are the light of the world, but ever since then, you have spoken only of him as the light and of the fact that we are in darkness. If this is true, how can we say that Christians are the light of the world? In fact, is it even possible?” The answer to these questions is that in himself the Christian cannot be the light of the world. However, he can show forth light to the extent that he first receives it from the Lord Jesus Christ and reflects it from him to others.
As I have studied this theme throughout the Bible I have been impressed by the fact that most of the images used to convey it clearly point this out. For instance, in the verses from the Sermon on the Mount that we are studying, the Christian is described as a lamp or a candle. He gives forth light. But he does so only because he first has been kindled by Jesus Christ. In John’s Gospel, John the Baptist is described as “a burning and a shining lamp” by Jesus. Again the point is that John’s light is secondary to that of Christ; John’s is a kindled light and exists only because of Christ.
One of the greatest illustrations on this point that I have heard was often used by Dr. Donald Grey Barnhouse. He used to say that when Christ was in the world he was a bit like the sun which is here by day and gone at night. But when the sun goes down the moon comes up, and the moon is a picture of the church—of Christians. It shines, but it does not shine by its own light. It shines only because it reflects the light of the sun. Jesus said of himself in John 8:12, “I am the light of the world.” But when he was thinking of the fact that one day he would be taken out of the world he said, “You are the light of the world.” And that is why the world is in such darkness today. At times the church is a full moon, in the midst of revival when a man like Luther or Calvin or Wesley is here. And at other times the church is a new moon and you can barely see it. But whether it is a full moon or a new moon or only a waxing or a waning quarter it glows because of the sun. In the same way, you and I can show forth light only if we reflect the real light of the Lord Jesus.
Do you do that? If you do, you will function a bit like Jesus himself when he was on earth, only in a smaller version. For one thing your presence will help to expose the evil and the darkness of this world, and you will find that you are not particularly popular for it. You will illuminate dishonest practices in business, gossip in the secretarial pool, loose talk and still looser morals at parties, corruption in local politics, racial prejudice, greed, selfishness, and other things. And they will appear darker, even to non-Christians, because of what you reveal of the holy character of Jesus.
For another thing, you will help faith grow among the weak in faith, just as a plant will grow even in a dark cave if a bright enough light is present. Friends should grow in the Christian life because of what you know and have learned of Jesus. If you are married and have children, the children should grow to full spiritual stature in your home.
Finally, you should also see men and women turn to Jesus himself through your testimony. In his day, the apostle Paul taught this by means of an illustration from the Old Testament. When Moses was with God in the mountain his face shone with transferred glory as a result of being with God. The glory was so bright that when Moses came down from the mountain he had to cover his face so that the light on it would not dazzle the people. Using this theme Paul argues in 2 Corinthians 3 and 4 that we also should shine with the same glory as a result of spending time with Jesus Christ, and that others should be able to see him as he is reflected by us. He concludes by saying, “God, who first ordered light to shine in darkness, has flooded our hearts with his light. We now can enlighten men only because we can give them knowledge of the glory of God, as we see it in the face of Jesus Christ” (2 Cor. 4:6 Phillips).
Do men see Jesus Christ in you? They will not find him in the world—in the world’s literature, culture, or pastimes. They will find him only as you look to Jesus, as you spend time with him and thereby allow some of his light to be reflected from your life to those about you.
You may be tempted to think that this applies only to “special” Christians. But the whole point of the illustration is that it applies to every believer in the Lord Jesus Christ. When Jesus Christ said, “You are the light of the world,” who were the “you’s” who heard him? They were not the important people alone, not even his disciples exclusively. They were the whole mass of those who followed him—rich and poor, small and great, educated and uneducated, Jews and Gentiles, free men and servants, women and children. These were all to reflect Christ’s light. And the nobodies (in the opinion of the world) were among them.
The Bible says that “God chose the foolish things of the world to shame the wise; God chose the weak things of the world to shame the strong. He chose the lowly things of this world and the despised things—and the things that are not—to nullify the things that are, so that no one may boast before him” (1 Cor. 1:27–29). No matter who you are, if you are a Christian, you are called to reflect Christ’s light to those about you.
Walk in the Light
Moreover, if you will do this, you also will find that the light of Christ will lead you on in love, grace, and righteousness and will keep you from falling as you move along the dark and treacherous paths of this world. Bishop Westcott, a great biblical scholar of a past generation, has a series of comments on this point that are so relevant to today’s world that they deserve repeating. He writes, “We lose the light if we do not follow Christ, and move as he moves. We cannot hold him back. It is the glory of our faith that it advances with the accumulated progress of all life. And it is our blessing that we are not left to grope sadly and restlessly for our way. That way is a track of light which grows dim only if we loiter or hang back. A Christian cannot rest in anything which has been already gained. New acquisitions of knowledge, new modes of thought, new forms of society, are always calling for interpretation, for recognition, for adjustment.… There are the trials of wealth burdened by an inheritance of luxury, which checks the growth of fellow-feeling and enfeebles the energy of Christian love. There are the trials of poverty worn by the struggle for bare existence, which exhausts the forces properly destined to minister to the healthy development of the fullness of life. There is the separation of class from class which seems to become wider with increasing rapidity through the circumstances of modern labor and commerce.… There is the impatient questioning of old beliefs which gives an unreal value to the appeal to authority and casts suspicion upon sympathetic efforts to meet doubt.
“But to meet all these dark problems our light—the Light of Life—is unexhausted and inexhaustible. The temple lamps blazed through the early night, but then at last they died out and darkness settled again over the city which lay below. Each borrowed and preparatory light gleamed for a time and afterwards faded away: such lights are consumed in burning. But the Light, which lightens because it lives … burns on with changeless splendour. And this only is required of us if we would know its quickening, cheering, warming energies, that we should follow it.”
Do we follow it? Do you? Oh, Christian, let us walk in the light, for then we walk with God. We do not escape the perils, foes, and dangers. But we do see them, and we see our proper path. In his light we see light. We reveal his light. And we do not overlook the goal.
14–15 As in v. 13, “you” is emphatic—namely, You, my followers and none others, are the light of the world. Though the Jews saw themselves as the light of the world (Ro 2:19), the true light is the Suffering Servant (Isa 42:6; 49:6), fulfilled in Jesus himself (Mt 4:16; cf. Jn 8:12; 9:5; 12:35; 1 Jn 1:7). Derivatively, his disciples constitute the new light (cf. Eph 5:8–9; Php 2:15). Light is a universal religious symbol. In the OT as in the NT, it most frequently symbolizes purity as opposed to filth, truth or knowledge as opposed to error or ignorance, and divine revelation and presence as opposed to reprobation and abandonment by God.
The reference to the “city on a hill” is at one level fairly obvious. Often built of white limestone, ancient towns gleamed in the sun and could not easily be hidden. At night the inhabitants’ oil lamps would shed some glow over the surrounding area (cf. Bonnard). As such cities could not be hidden, so also it is unthinkable to light a lamp and hide it under a peck measure (v. 15, NIV, “bowl”). A lamp is put on a lampstand to illuminate all. Attempts to identify “everyone in the house” as a reference to all Jews in contrast with Luke 11:33, referring to Gentiles (so Manson, Sayings of Jesus, 93), are probably guilty of making the metaphor run on all fours, especially in view of the Gentile theme so strongly present in Matthew.
But the “city on a hill” saying may also refer to OT prophecies about the time when Jerusalem or the mountain of the Lord’s house, or Zion, would be lifted up before the world, the nations streaming to it (e.g., Isa 2:2–5; cf. chs. 42, 49, 54, 60). This allusion has been defended by Grundmann, Trilling (Das wahre Israel, 142), and especially K. M. Campbell (“The New Jerusalem in Matthew 5.14,” SJT 31 : 335–63). It is not a certain allusion, and the absence of definite articles tells against it; if valid, it insists that Jesus’ disciples constitute the true locus of the people of God, the outpost of the consummated kingdom, and the means of witness to the world—all themes central to Matthew’s thought.
16 Jesus drives the metaphor home. What his disciples must show is their “good works,” i.e., all righteousness, everything they are and do that reflects the mind and will of God. And people must see this light. It may provoke persecution (vv. 10–12), but that is no reason for hiding the light others may see and by which they may come to glorify the Father—the disciples’ only motive (cf. 2 Co 4:6; 1 Pe 2:12). Witness includes not just words but deeds; as Stier (Words of the Lord Jesus) remarks, “The good word without the good walk is of no avail.”
Thus the kingdom norms (vv. 3–12) so work out in the lives of the kingdom’s heirs as to produce the kingdom witness (vv. 13–16). If salt (v. 13) exercises the negative function of delaying decay and warns disciples of the danger of compromise and conformity to the world, then light (vv. 14–16) speaks positively of illuminating a sin-darkened world and warns against a withdrawal from the world that does not lead others to glorify the Father in heaven. “Flight into the invisible is a denial of the call. A community of Jesus which seeks to hide itself has ceased to follow him” (Bonhoeffer, Cost of Discipleship, 106).
5:13–16 / In contrast to those who oppose the work of God in the world (cf. 5:11), the followers of Christ (you is emphatic in the Greek text) are the salt of the earth. Salt was a basic and necessary item in ancient culture. It was used as a preservative, as a purifier, and as a seasoning. In the immediate context Jesus seems to be saying that those who live out the qualities listed in the Beatitudes will permeate the world and retard its moral and ethical decay. As Tasker notes, the most obvious general characteristic of salt is its essential difference from the medium in which it is placed (p. 63). The righteous conduct of believers keeps society from turning completely rancid. If salt should somehow lose its saltiness, there is no way to make it salty again; it has become worthless and should be thrown away. Although salt does not normally lose its strength, the possibility is mentioned to stress the necessity of believers maintaining their distinctive mission in the world. Explaining how salt can be adulterated with an inexpensive white powder to increase profit is unnecessary. It is the metaphor itself, not the image it employs, that is being extended. To be thrown out and trampled underfoot means that unless the disciples maintain their role as salt in the world they will become useless and will be rejected.
Believers are also the light of the world. God said to Israel, “I will also make you a light for the Gentiles, that you may bring my salvation to the ends of the earth” (Isa. 49:6; cf. 42:6). The servant role of Israel is taken over by Jesus (John 8:12; 9:5) and passed on to his followers. Light is intended for illumination. It is for seeing. Cities built on hills cannot be hidden. How foolish it would be to light a lamp and then place it under a tub. Lamps are to be placed on lampstands; that way everyone in the house can see.
The followers of Jesus are to be like lamps on a lampstand. They are to let their light shine (aorist third person imperative) so that people will see their good deeds and give praise to God. Note that the light does not originate with believers; they are to let it shine. The light is seen in the good things they do. It is less a message directed to the intellect than a way of life lived out before others. When outsiders see that following Christ leads to a life of good deeds, they will praise not the believer but the believer’s Father in heaven.
If the Beatitudes leave the impression that life in the kingdom is somewhat passive, the metaphors of salt and light correct such a misunderstanding. Salt permeates and performs its vital function in society. Light illumines the darkness and points people to the One who is the source of all light and life.
Jesus speaks of our influence (5:13–16)
We are meant to be salt and light in society, and we shall be if the characteristics of the blessed life are seen in us.
There’s a purity about salt: the Jewish sacrifices were offered with it. Salt is a preservative. But most of all, we look to salt for flavour. And that is what Christians are meant to be. If they are insipid they are useless to their Lord. There should be a flavour of Christlikeness, a sparkle of joy and unselfishness about them that is immensely attractive.
The light, too, is a most evocative image. A light is often a warning; think of a lighthouse. It is often an attraction; think of a lighted window looming out of the fog when you are lost. A light is often a guide; think of a torch or a flare path. Above all, a light is visible. You don’t hide a lamp under an inverted bowl; you put it on a stand. There is no excuse for secret discipleship. ‘A city on a hill cannot be hidden’ (5:14). And all this is possible only because Christ is the light of the world. Until he has illuminated us we can never shine with his reflected light. The imperative of shining is based on the indicative of being lit up by him. Then people will see our good deeds and praise not us but our heavenly Father, who is the source of the light they see reflected.
Both images have something important to say about Christian involvement in society. They militate against all forms of separation and withdrawal. We are meant to get involved and be a light and a preservative. We are not promised that we shall be able to Christianize the legislation and values of the world, but we are challenged to be an irritant, marching to a different drum and calling on society to heed God’s standards.
 MacArthur, J. F., Jr. (1985). Matthew (Vol. 1, pp. 235–247). Chicago: Moody Press.
 Boice, J. M. (2002). The Sermon on the Mount: an expositional commentary (pp. 67–72). Grand Rapids, MI: Baker Books.
 Carson, D. A. (2010). Matthew. In T. Longman III & D. E. Garland (Eds.), The Expositor’s Bible Commentary: Matthew–Mark (Revised Edition) (Vol. 9, pp. 169–170). Grand Rapids, MI: Zondervan.
 Mounce, R. H. (2011). Matthew (pp. 42–43). Grand Rapids, MI: Baker Books.
 Green, M. (2001). The message of Matthew: the kingdom of heaven (pp. 91–92). Leicester, England; Downers Grove, IL: InterVarsity Press.