You are the salt of the earth; but if the salt has become tasteless, how can it be made salty again? It is no longer good for anything, 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 does anyone light a lamp and put it under a basket, but on the lampstand, and it gives light to all who are in the house.—Matt. 5:13–15
With great responsibility, there is often great danger. We can’t be an influence for purity in the world if we have compromised our own purity. We can’t sting the world’s conscience if we continually go against our own. We can’t be used of God to retard the corruption of sin in the world if our lives become corrupted by sin. To lose our saltiness is not to lose our salvation, but we will lose our effectiveness.
Light, too, is in danger of becoming useless. Like salt, it can’t lose its essential nature. A hidden light is still light, but it is useless light. That’s why people do not “light a lamp and put it under a basket, but on the lampstand, and it gives light to all who are in the house.” A light that is hidden under a basket can’t even be used to read by; it helps neither the person who hides it nor anyone else.
Don’t hide your light for fear of offending others, whether out of indifference or lovelessness or any other reason. If you do, you demonstrate unfaithfulness to the Lord.
The demands of purity call for more than merely the eradication of sin and shameful habits, but also for replacing impurity with active, living, breathing righteousness. What are some specific acts of obedience and service to which God is calling you at this hour, in this generation?
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 spoilation; 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 hellishhess (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 fiat 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.
13 Salt and light are such common substances (cf. Pliny, Nat. 31.102: “Nothing is more useful than salt and sunshine”) that they doubtless generated many sayings. Therefore it is improper to attempt a tradition history of all gospel references as if one original stood behind the lot (cf. Mk 4:21; 9:50; Lk 8:16; 11:33; 14:34–35). Equally, the suggestion that Jesus is referring to the “covenant of salt” (Lev 2:13; Nu 18:19; 2 Ch 13:5) seems unlikely. Where that expression shows up in the OT, it seems to be connected with the permanence or stability of God’s covenant with his people. Here, however, Jesus says that his disciples are “salt.” There is no mention of covenant, and, far from symbolizing stability, the salt of which Jesus speaks loses its effectiveness.
The reality is that “salt” is not a technical word with only one set of associations. It can even be connected with judgment (Lot’s wife is turned into a pillar of salt, Ge 19:26; one might ruin an enemy’s field by sowing it with salt, Jdg 9:45). Salt was used in the ancient world to flavor foods and even in small doses as a fertilizer (cf. Eugene P. Deatrick, “Salt, Soil, Savor,” BA 25 : 44–45, who wants tēs gēs to read “for the soil,” not “of the earth”; but notice the parallel “of the world” in v. 14). Sometimes the word is simply referring to a commodity (Ezr 6:9) or identifies a place (2 Sa 8:13). Above all, salt was used as a preservative. Rubbed into meat, a little salt would slow decay. Strictly speaking, salt cannot lose its saltiness; sodium chloride is a stable compound. But most salt in the ancient world derived from salt marshes or the like rather than by evaporation of salt water, and therefore contained many impurities. The actual salt, being more soluble than the impurities, could be leached out, leaving a residue so dilute it was of little worth.
In modern Israel, savorless salt is still said to be scattered on the soil of flat roofs. This helps harden the soil and prevent leaks; and since the roofs serve as playgrounds and places for public gathering, the salt is still being trodden under foot (Deatrick, “Salt, Soil, Savor,” 47). This explanation negates the attempt by some (e.g., Lenski, Schniewind) to suppose that, precisely because pure salt cannot lose its savor, Jesus is saying that true disciples cannot lose their effectiveness. The question “How can it be made salty again?” is not meant to have an answer, as Schweizer rightly says. The rabbinic remark that what makes salt salty is “the afterbirth of a mule” (mules are sterile) rather misses the point (cf. Schweizer). The point is that if Jesus’ disciples are to act as a preservative in the world by conforming to kingdom norms, if they are “called to be a moral disinfectant in a world where moral standards are low, constantly changing, or nonexistent …, they can discharge this function only if they themselves retain their virtue” (Tasker).
13 The verb μωρανθῇ (mōranthē, “loses its saltiness,” GK 3701) is used four times in the NT. In Luke 14:34, it again relates to salt, but in Romans 1:22 and 1 Corinthians 1:20, it has its more common meaning “to make or become foolish” (cf. cognate μωρέ [mōre, “fool”] in v. 22). It is hard not to conclude that disciples who lose their savor are in fact making fools of themselves. The Greek may hide an Aramaic תפל (tpl, “foolish”) and תבל (tbl, “salted”; see Black, Aramaic Approach, 166–67).
(2) Light (5:14–16)
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).
15 There are several probable Semitisms in this verse (cf. Hill). The μόδιος (modios, “bowl,” GK 3654) is a wooden grain measure, usually given as 8¾ liters, i.e., almost exactly one peck (see comments at 13:33). It is doubtful whether the vessel was used for hiding light, despite various suggestions. A different word is used in Josephus (Ant. 5.223 [6.5]). In any case, Jesus’ point turns on what is not done.
 MacArthur, J. (2008). Daily readings from the life of Christ (p. 95). Chicago: Moody Publishers.
 MacArthur, J. F., Jr. (1985). Matthew (pp. 233–247). Chicago: Moody Press.
 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. 168–171). Grand Rapids, MI: Zondervan.