Biblical Commentary
(Bible study)
Matthew 5:13-20



13“You are the salt of the earth, but if the salt has lost its flavor, with what will it be salted? It is then good for nothing, but to be cast out and trodden under the feet of men.

“You are the salt of the earth” (v. 13a). “You” sets the listeners apart from other people (scribes, Pharisees, etc.), who are not the salt of the earth. It is plural, and thus describes the church. Christ calls us both individually and collectively to be the salt of the earth.

Note that Jesus doesn’t say, “You will be the salt of the earth” or “You have within you the potential to become the salt of the earth.” He says, “You ARE the salt of the earth”—indicating that, by God’s grace, the miracle of our transformation has already begun.

Salt has little influence while sitting in a salt shaker. However, it is of great value once it is mixed, in the right proportions, in our food. When it is sprinkled on food—or, better yet, cooked into food—it transforms the food. So also, Christians sitting alone in the comfort of their homes are unlikely to make much of a difference to the people outside their door—the people who need Christ. It is as we rub elbows with others, both Christians and non-Christians, that we have the opportunity to bring a Christ-like flavor to their lives. However, we must always stay alert so that we impart a Christ-like flavor to them rather than allowing them to impart a secular flavor to our lives.

People value salt. They use it not only for seasoning, but also as a preservative for food. Like eyeglasses, its usefulness exceeds its size. Salt is inexpensive but, if it were not, we would still require it—not only to enhance or to preserve food, but also to sustain life.

Salt then is a perfect metaphor for the people of God:

•We have a responsibility to transform the environment in which we find ourselves, just as salt transforms food.

• We are often few in number, but it is no matter. Just as a few grains of salt can make a big difference in food, so also a few faithful Christians can make a big difference in the world.

“but if salt has lost its flavor (moranthe—from moraino), with what will it be salted?” (v. 13b). The Greek word moraino has more than one meaning. It can mean “lost its taste,” but it can also mean “become foolish.” Matthew was undoubtedly aware of this double meaning and used the word moraino to convey the fact that the disciple who loses his/her spiritual zest has, as a consequence, also become foolish. Foolishness is an important theme in this Gospel (7:26; 23:17; 25:1-12). Fools—those who fail to heed the scriptures—are bound to suffer the consequences of their foolishness.

Jesus warns us not to be complacent. If salt loses its taste, it becomes worthless. Salt cannot change its chemical composition, but it does lose taste and value if adulterated. In Jesus’ day, much salt was recovered from the Dead Sea and was adulterated with various substances. At some point, the adulteration could become so pronounced that people would discard the salt as worthless.

The danger for the church today is that it is tempted to give too much credence to the values generated by the world and too little to the values found in the Bible. Someone has said that, to learn what the church will be saying in five years, just familiarize yourself with what the world is saying today. There is a good deal of truth in that, but the interval is often much less than five years. The church is always in danger of allowing the world to infiltrate. When that happens, we cease to be salt and become “good for nothing, but to be cast out and trodden under the feet of men.”


14“You are the light of the world. (Greek: kosmou) A city located on a hill can’t be hidden. 15Neither do you light a lamp, and put it under a measuring basket, but on a stand; and it shines to all who are in the house. 16Even so, let your light shine before men; that they may see your good works, and glorify your Father who is in heaven.”

“You are the light of the world” (kosmou—from kosmos) (v. 14a). The word kosmos is significant. In the New Testament, kosmos is often used to mean the world that is opposed to God. The kosmos loves “the darkness rather than the light; for their works (are) evil” (John 3:19). However, “God so loved the world, that he gave his one and only Son, that whoever believes in him should not perish, but have eternal life” (John 3:16). Jesus has appointed us to bring light to dispel the darkness of the kosmos. It is a sacred duty.

Kosmos is also a significant word in another sense. The kosmos is the whole world—the East, the West, and everything in between. Christ calls us to light up the whole globe. He says, “Go, and make disciples of all nations (Matthew 28:19). Not everyone can go to a foreign mission field, but there are plenty of mission fields in our own communities. And we can all support foreign missionaries by our prayers and financial support. And we can all keep our ears to the ground to hear what Christ is calling us to do. It is just possible that he might call us to a faraway place, either for a short time or for a lifetime.

Light is a familiar metaphor in scripture:

• Psalm 36:9 says of God, “in your light we see light.”

• Psalm 119:105 says of the scriptures, “Your word is a lamp to my feet and a light to my path.”

• Isaiah 42:6 told Israel that God intended them to be “a light to the nations,” i.e., to all the world.

• Jesus adopted the metaphor for himself in John 9:5, saying, “While I am in the world, I am the light of the world.”

• Here, Jesus says to his disciples, “You are the light of the world.” Jesus’ tenure on earth was limited. He charges his disciples with providing illumination through the witness of their good works (v. 16).

Our light is derived from our relationship to Christ. Our light is not our own, but is the reflection of Jesus’ light.

“Neither do you light a lamp, and put it under a measuring basket, but on a stand; and it shines to all who are in the house” (v. 15). But if we are not to seek glory for ourselves, neither are we to be invisible. A city is set on a hill where it can be seen. A lamp is set upon a lampstand where it can provide light for the house.

“Even so, let your light shine before men; that they may see your good works, and glorify your Father who is in heaven” (v. 16). Like lamps, disciples have a purpose. We are to live in such a way that our good works give glory to God.

Good works are in keeping with the principle of Christian love. If we love one another, our love will be manifested in acts of mercy. Such acts are highly effective ways to give God glory. People who reject the church and its teachings cannot easily dismiss the witness of those who devote themselves to the service of others. Sacrificial service draws people to Christ. Mother Teresa is the classic example, but every community has its saints who devote themselves quietly and powerfully to the service of those in need. They are, indeed, the light of the world.

Christ intends each of us to be a light—some smaller and some larger, but all shining brightly—a thousand points of light—a million points—a billion! If every Christian had his/her light turned on, this would be a very different world!

The purpose of all these good works is not to garner personal honors (see Matthew 6:1-8), but is instead to “give glory to your Father in heaven.” Everything in our ministry needs to point to the Father.


17“Don’t think that I came to destroy the law or the prophets. I didn’t come to destroy, but to fulfill. 18For most certainly, I tell you, until heaven and earth pass away, not even one smallest letter or one tiny pen stroke shall in any way pass away from the law, until all things are accomplished. 19Whoever, therefore, shall break one of these least commandments, and teach others to do so, shall be called least in the Kingdom of Heaven; but whoever shall do and teach them shall be called great in the Kingdom of Heaven. 20For I tell you that unless your righteousness exceeds that of the scribes and Pharisees, there is no way you will enter into the Kingdom of Heaven.”

“Don’t think that I came to destroy the law or the prophets” (v. 17a). The law was the Torah—the first five books of the Hebrew Scriptures. The prophets were people chosen by God to speak for him—to deliver his words of judgment and grace. The law and the prophets together symbolized the whole will of God. They were intended to guide the people faithfully so that they could live within the will of God and enjoy God’s blessings.

This is a difficult passage, because Jesus’ teaching about the law here seems to be in conflict with his observance elsewhere. Here he defends the law in detail. Elsewhere, he defended his disciples for plucking grain on the Sabbath (12:1-6). He healed people on the Sabbath (12:10-13). He defended his disciples when they failed to observe ritual handwashing (15:1-9). And yet, in this passage, Jesus appears to be calling for a super-meticulous observance of the law.

In Jesus’ day, Jews were subject not just to the law of the Torah but also to the Mishnah (commentary on the Torah) and the Talmud (commentary on the Mishnah). These commentaries comprised thousands of rules defining acceptable and unacceptable behavior under the Torah. For instance, the rules defined what it meant to work. To carry a burden was work, but that had to be defined. Precisely how much (if anything) might a person carry before it counted as work. The scribes dedicated their lives to answering that sort of question.

Jesus respected the law, but he had little tolerance for the thousands of rules generated by the scribes. That was the source of much of the conflict between him and the scribes and Pharisees.

“I didn’t come to destroy, but to fulfill” (v. 17b). Jesus said that he had not come to destroy the law and prophets, but to fulfill them. What does that mean? Jesus came really to bring out the real meaning of the Law, which had its roots in love for God and love for neighbor.

Perhaps a fitting metaphor would be a visit to a high school orchestra by a concert violinist. The students would be learning rules about music. While they might follow the rules carefully, their music would nevertheless be amateurish. The concert violinist, on the other hand, would have long since internalized the rules and would thus be free to be guided by the spirit of the music instead of rules. Her mature understanding would allow her to flow with the music and to render it beautifully. Observing her, the students would learn a great deal about music that would go beyond anything that rules could ever teach.

The Jewish people focused on the law, but their observance of the law was less than perfect. They often observed the rules without embodying its spirit. Jesus, the incarnate Word of God, embodied the law perfectly, fulfilling its deepest meaning. Observing him, we learn a great deal about oneness with God and God’s will that we could never learn from the law. It is in that sense that Jesus fulfills the law and the prophets.

“For most certainly, I tell you, until heaven and earth pass away, not even one smallest letter or one tiny pen stroke shall in any way pass away from the law, until all things are accomplished” (v. 18). In this context, the phrase, “heaven and earth,” mean the totality of creation. God intended his laws to bless the people of his created order—to help them to avoid the aberrant behaviors that would threaten to undo them.

Each commandment is important. What if we were to keep all the laws except “You shall have no other gods before me” (Exodus 20:2)? Failing to keep that commandment would cause the rest of the commandments to unravel. What if we were to keep all of the laws except “You shall not murder” (Exodus 20:4)? Failing to keep that one law would make our world a murderous place to live. What if we were to keep all the commandments except “You shall not commit adultery” (Exodus 20:14)? We can actually see the results of the failure to keep that commandment, because many people today disregard that commandment. In the wake of people’s adulterous liaisons, spouses suffer—children suffer—the adulterers suffer—and the fabric of our society is ripped.

“until all things are accomplished” (v. 18b). When will this be? There are three possibilities:

• Until the end of the world.

• Until the church abides by the spirit of the law.

• Until Jesus’ death and resurrection usher in a new age (Senior, 75).

“Whoever, therefore, shall break one of these least commandments, and teach others to do so, shall be called least in the Kingdom of Heaven; but whoever shall do and teach them shall be called great in the Kingdom of Heaven” (v. 19). Jesus doesn’t offer us the option of championing particular commandments and ignoring others. If Jesus is to be Lord of our lives, we must guide our lives by the totality of his teachings. We will, of course, never do that perfectly in this life, but making Jesus and his teachings our North Star should be our goal.

I don’t remember many sermons from my childhood, but I do remember one. The preacher was preaching on the creation story in Genesis. He noted that God had told the man that he must not eat of the fruit of the tree of the knowledge of good and evil, “for in the day that you eat of it you will surely die” (Genesis 2:17). But Satan came along a little later, saying, “You will not surely die.”

God’s words and Satan’s words were nearly the same. The only difference was Satan’s addition of the word “not”—but that little word reversed the meaning. I have known a number of people, including some clergy, who make little changes like that—or dodge particular scripture passages that they don’t like—in an attempt to re-shape scripture to fit their personal beliefs. To do that is to put oneself in peril.

“least in the Kingdom of Heaven” (v. 19b). This verse suggests that there will be rankings in heaven (see also 11:11; 18:1, 4; 20:21).

“For I tell you that unless your righteousness exceeds that of the scribes and Pharisees, there is no way you will enter into the Kingdom of Heaven” (v. 20). The scribes pride themselves on their ability to interpret the law correctly, and the Pharisees pride themselves on keeping the law in all of its detail. They represent the religious establishment in Israel. Jesus challenged their authority, and they become his mortal enemies.

There are a number of problems with the scribes and Pharisees. They seek the glory that belongs to God (6:2, 5). They honor God with their lips, but their hearts are far from him (15:8). They teach human precepts as doctrines (15:9; 23:16-22). They fail to observe the weightier matters of the law (23:23). While they look presentable on the outside, “within they are full of hypocrisy and iniquity” (23:28). Jesus calls them hypocrites on a number of occasions (6:5, 16; 15:7; 22:18; 23:13-29). The greatest of their failures, however, is their spiritual pride—their inclination to preen in their spiritual mirrors and to congratulate themselves on the beautiful images they see reflected there. They claimed to honor God, but much of their energy was directed at self-glorification.

It isn’t easy to avoid the sins of the Pharisees. When we read about them, we are tempted to pray, “God, I thank you that I am not like these Pharisees” (Luke 18:11). When that happens, we have adopted their spiritual pride.

Verses 17-20 lead into the antitheses that follow in verses 21-48, and that give us a final clue as to Jesus claim that he fulfills the law and the prophets. In verse 20, Jesus demands that our righteousness exceed that of the scribes and Pharisees, demanding far more of us than anyone had expected before. In verses 21-48, Jesus takes teaching about anger, adultery, divorce, oaths, retaliation and love to new realms. We can hardly read them, because their demands are so crushing. Perhaps they are Jesus’ way of forcing us to acknowledge our need for grace.

SCRIPTURE QUOTATIONS are from the World English Bible (WEB), a public domain (no copyright) modern English translation of the Holy Bible. The World English Bible is based on the American Standard Version (ASV) of the Bible, the Biblia Hebraica Stutgartensa Old Testament, and the Greek Majority Text New Testament. The ASV, which is also in the public domain due to expired copyrights, was a very good translation, but included many archaic words (hast, shineth, etc.), which the WEB has updated.


Allen, Ronald J., in Roger Van Harn (ed.), The Lectionary Commentary: Theological Exegesis for Sunday’s Text. The Third Readings: The Gospels (Grand Rapids: Eerdmans, 2001)

Barclay, William, The Daily Bible Study: The Gospel of Matthew, Vol. 1 (Edinburgh: The Saint Andrew Press, 1956)

Blomberg , Craig L., New American Commentary: Matthew, Vol. 22 (Nashville: Broadman Press, 1992)

Boring, M. Eugene, The New Interpreter’s Bible, Vol. VIII (Nashville: Abingdon, 1995)

Bruner, Frederick Dale, Matthew: Volume 1, The Christbook, Matthew 1-12 (Dallas: Word, 1987)

Johnson, Sherman E. and Buttrick, George A., The Interpreter’s Bible, Vol. 7 (Nashville: Abingdon, 1951)

Gardner, Richard B., Believers Church Bible Commentary: Matthew (Scottdale, Pennsylvania: Herald Press, 1990)

Hare, Douglas R. A., Interpretation: Matthew (Louisville: John Knox Press, 1993)

Keener, Craig S., The IVP New Testament Commentary Series: Matthew, (Downers Grove, Illinois: InterVarsity Press, 1997)

Long, Thomas G., Westminster Bible Companion: Matthew (Louisville: Westminster John Knox Press, 1997)

MacArthur, John, Jr., The MacArthur New Testament Commentary: Matthew (Chicago: The Moody Bible Institute, 1985)

Morris, Leon, The Gospel According to Matthew (Grand Rapids, Eerdmans, 1992)

Senior, Donald, Abingdon New Testament Commentaries: Matthew (Nashville: Abingdon Press, 1998)

Sweet, Leonard, “Lamplight vs. Starlight,” Homiletics, Feb. 4, 1996.

Copyright 2006, 2018 Richard Niell Donovan