Matthew 5:13-20

“You are the salt of the earth; but if salt has lost its taste, how can its saltiness be restored? It is no longer good for anything, but is thrown out and trampled underfoot. 14“You are the light of the world. A city built on a hill cannot be hid. 15No one after lighting a lamp puts it under the bushel basket, but on the lampstand, and it gives light to all in the house. 16In the same way, let your light shine before others, so that they may see your good works and give glory to your Father in heaven. 17“Do not think that I have come to abolish the law or the prophets; I have come not to abolish but to fulfill. 18For truly I tell you, until heaven and earth pass away, not one letter, not one stroke of a letter, will pass from the law until all is accomplished. 19Therefore, whoever breaks one of the least of these commandments, and teaches others to do the same, will be called least in the kingdom of heaven; but whoever does them and teaches them will be called great in the kingdom of heaven. 20For I tell you, unless your righteousness exceeds that of the scribes and Pharisees, you will never enter the kingdom of heaven.”

When Salt Loses Its Saltiness

Many years ago, there was a small coastal town that depended on one thing to make it through the long, harsh winters: salt. Fishermen packed their catch in salt, families preserved meat with salt, and even the roads were treated with salt to melt the snow and ice.

One year, a shipment of salt arrived that looked perfect. It was white, grainy, and filled every barrel. But something was wrong. When they used it to preserve meat, the meat spoiled. When they tried to melt the ice, the ice remained. The salt looked like salt—but it had no strength. It had lost its distinctiveness, its purpose.

In that winter, the town discovered a sobering truth: salt that is not truly salty is worse than useless—it gives a false sense of security.

Stories like this remind us that when something loses the very quality that makes it what it is, it cannot fulfill its purpose. So it is with our lives and our faith when we lose the distinctiveness we were meant to have.

In Matthew 5:13–20, Jesus looks at His disciples—ordinary people, not the religious elites—and says: “You are the salt of the earth … You are the light of the world.” Then He explains that He has not come to abolish the Law or the Prophets, but to fulfill them. In these words, He shows us who He is, who we are in Him, and what it means to live as His people under the new covenant.

“You are the salt of the earth… You are the light of the world.”

Notice Jesus does not say, “Try to become salt and light.” He says, “You are the salt of the earth… You are the light of the world.” This is not a command; it is a declaration of identity.

This identity flows from our union with Christ. By nature, we are not salty—we are spiritually dead in sin (Ephesians 2:1). We are not light—we walk in darkness (John 3:19). But God, by sheer grace, unites us to Christ through faith. And because He is the Light of the World (John 8:12), those who are in Him share in His light. 

Salt: Preserving and Distinct

In the ancient world, salt did two main things:

1. It preserved. It slowed decay.

2. It flavored. It made food distinct and delightful.

The world is like meat left alone—it decays morally, spiritually, and relationally. Church doctrines teach that every part of human nature is touched by sin. Left to ourselves, we do not drift upward toward holiness; we drift downward into corruption.

So, God sprinkles His people—His church—throughout the world to act as a preserving influence, slowing the spread of evil, bearing witness to righteousness, truth, and grace.

But salt is only effective if it is distinct. When believers become indistinguishable from the world in our loves, our ethics, our priorities, and our worship, we lose our saltiness. We may still call ourselves Christians, but our witness becomes like that worthless salt in that coastal town—present in appearance, but powerless in effect.

Light: Visible and Intended to Shine

“A city set on a hill cannot be hid. No one, after lighting a lamp, puts it under the bushel basket.”

Light does not brag about itself; it simply shines and reveals reality. Light exposes what is hidden in darkness, and it guides people safely along the path.

Jesus is the true Light, and in union with Him, the church is a community of light. Notice, He says, “a city set on a hill”—not just individual flashlights, but a community whose shared life together is meant to be seen.

He also gives the reason, “…so that they may see your good works and give glory to your Father in heaven.”

Our good works are the fruit of salvation, not the root. They are not the cause of our acceptance with God, but the evidence that God has already accepted us in Christ. When people see Spirit-produced good works—justice, mercy, integrity, generosity, sacrificial love—they see something that cannot be explained merely by human effort. And when they ask, Why are you like this? The answer points away from us and toward our Father in heaven.

If you began quietly visiting an elderly neighbor every week. Bring meals, read Scripture, and pray. Never post about it, never announce it at church, never think of it as anything remarkable.

Over time, other neighbors notice. One day, someone asks, “Why are you doing all this? You’re busy, you have your own family.” And you simply reply, “Christ has loved me when I was helpless; how can I not love my neighbor?”

Such unseen faithfulness is a lamp on a stand. That might prompt others to ask questions about Jesus. A light shone, and people gave glory—not to you—but to our Father in heaven.

This is an example of salt and light. I know people like this. Unfortunately, not enough people. How do we live this truth faithfully? That leads us to what Jesus says next.

2. Christ’s Work: The Fulfillment of the Law (vv. 17–18)

“Do not think that I have come to abolish the law or the prophets; I have come not to abolish but to fulfill.”

Jesus anticipates a misunderstanding. As He preaches grace, as He welcomes sinners, as He exposes the hypocrisy of the religious leaders, some might assume that He is setting aside the Old Testament. He is abolishing God’s Law.

Jesus says, “No. I did not come to abolish, but to fulfill.”

This is a crucial statement. Christ fulfills the Law and the Prophets in several ways:

1. He fulfills their predictions. All the prophecies, types, and shadows—temple, priesthood, sacrifices, feasts—point forward to Him, the true Passover Lamb, the true High Priest, the true Temple.

2. He fulfills their demands. God’s Law requires perfect, personal, perpetual obedience. We cannot provide that. But Christ does. As our representative, He obeys the Law in our place—loving God with all His heart, soul, mind, and strength, and loving His neighbor perfectly.

3. He fulfills their penalties. The Law also pronounces a curse on disobedience. On the cross, Jesus bears that curse for His people. He takes the condemnation that the Law pronounces on sinners.

This means the Law reveals two things very clearly: The holiness of God and our inability to meet those standards.

But the gospel reveals a third, glorious thing: The sufficiency of Christ, who keeps the Law for us and bears the Law’s curse in our place.

So, when Jesus says, “not an iota, not a dot, will pass from the Law until all is accomplished”, He is saying that God’s moral will has not changed, and every promise, every type, every shadow will find its completion in Him.

This is the foundation of the new covenant. Jeremiah 31 promised a day when God would write His Law on His people’s hearts and remember their sins no more. That promise is fulfilled in Jesus.

3. Our Calling: New-Covenant Love in a Dark World (vv. 19–20)

“Whoever breaks one of the least of these commandments, and teaches others to do the same, will be called least in the kingdom of heaven; but whoever does them and teaches them will be called great in the kingdom of heaven.”

These are sobering words. Jesus warns us against minimizing God’s commands— The Greek word, λύω LUŌ, translated as break, can also mean to loosen, or relax. We don’t even have to break the commandments; we only have to loosen or relax them to break God’s covenant LAW. 

He also warns against a merely external, performance-based righteousness like that of the Pharisees.

How can our righteousness exceed that of the Pharisees?

1. Imputed Righteousness (Justification)
The moment we trust in Christ, God credits us with the perfect righteousness of Jesus. Our sins are counted to Him; His obedience is counted to us. In this sense, our righteousness does not just exceed that of the Pharisees—it is the very righteousness of Christ.

2. Imparted Righteousness (Sanctification)
The Holy Spirit then begins to actually transform us from the inside out. He renews our hearts, changes our desires, and empowers real obedience. This is not to earn God’s love, but because we already have it.

Under the new covenant, the Law is no longer a ladder to climb to heaven; it is a path we walk in gratitude, empowered by the Spirit.

The New Commandment of Love

Jesus later summarizes this new-covenant ethic very clearly:

• “A new commandment I give to you, that you love one another: just as I have loved you…” (John 13:34)

• “You shall love the Lord your God with all your heart… and your neighbor as yourself.” (Matthew 22:37–39)

This is not a soft, sentimental love. It is cross-shaped, covenantal, sacrificial love. It is the love that He has shown us: He loved us when we were unlovely; He pursued us when we were running away; He laid down His life for enemies and made them friends. And now He says, “As I have loved you, so you also are to love one another.”

Our Reformed confessions say that good works are done out of true faith, according to God’s Law, and for His glory. At the center of those good works is Spirit-empowered love.

So what does this mean for us, here and now?

1. Rest in Christ as the Fulfillment of the Law.
Stop trying to relate to God as if your obedience earns His favor. Confess your sin. Trust that Jesus has fulfilled the Law and borne its curse for you. Receive His righteousness by faith alone.

2. Ask the Spirit to Write God’s Law on Your Heart.
Pray: “Lord, make me love what You command. Change my desires. Make Your will my delight.” This is the promise of the new covenant—to transform you from the inside out.

3. Choose Concrete Acts of Love.
Do not leave this sermon in the realm of theory. Ask: Who in my church family needs encouragement, a visit, a phone call? Who in my neighborhood is lonely, grieving, or in need? Where can I show Christlike love at work, at school, in my home this week? Then, in faith, do something small but real—an invitation to dinner, an offer to pray, a practical gift, a listening ear.

4. Guard Your Saltiness; Let Your Light Shine.
Examine your life: Where have I become indistinguishable from the world’s values? Where have I hidden my light out of fear, shame, or comfort? Bring these to Jesus. He forgives, restores, and calls you again: “You are the salt of the earth… You are the light of the world.”

5. Love One Another in the Pattern of the Cross.
Remember, the new commandment is not just “love one another” but “as I have loved you.” That means: Love when it is inconvenient, Love when there is no applause,  Love when you must forgive, Love when it costs you something.

Benediction: