Matt 7:15–23 — A Healthy Tree Bears Good Fruit

The title of this sermon comes from Matthew 7:17: “Every healthy tree bears good fruit.”

We are in the third and concluding section of the Sermon on the Mount. The Beatitudes form the first part, and the central section presents Jesus’ teaching on kingdom righteousness. The conclusion calls hearers to follow Christ: enter the narrow gate, bear good fruit, and build upon the rock so that the house withstands the coming judgment.

This final section repeatedly refers to eschatological judgment. Every tree that does not bear good fruit is cut down and thrown into the fire. Christ tells false professors, “I never knew you; depart from me, you workers of lawlessness.” The concluding parable describes a storm that destroys the house built on sand. Fire, exclusion from Christ’s presence, and the destructive storm all portray the day when humanity will stand before Christ.

How do we escape judgment and enter life? A surface reading might suggest salvation by doing everything Jesus commands. Verse 21 says that the one who does the Father’s will enters the kingdom, and verse 24 commends the person who hears Christ’s words and does them.

Jesus certainly calls his disciples to obedience, but before doing comes entering. As verses 13–14 teach, we must enter by the narrow gate. The gate represents Christ himself—the one who is “the way, and the truth, and the life” and the door through which the sheep enter. We receive his gospel and salvation through faith.

Obedience follows entrance through the gate. Genuine faith produces good fruit, and that fruit appears in the obedience of the wise builder. The entire concluding section must therefore be read as a unit about faith and its fruit. We enter through faith in Christ, build upon Christ the rock, and then manifest faith’s reality through obedience.

Beware of False Prophets

Within this discussion of faith and fruit, Jesus introduces a warning: “Beware of false prophets, who come to you in sheep’s clothing but inwardly are ravenous wolves.”

The warning fits the context because the narrow gate is Christ and the true way of salvation is his gospel. Others will claim to reveal another gate or path. Jesus, the true prophet, warns his disciples not to follow false prophets who teach a false way of salvation.

The apostles repeat his warning. Paul told the Ephesian elders, “Pay careful attention to yourselves and to all the flock, in which the Holy Spirit has made you overseers.” He knew that after his departure “fierce wolves” would enter and refuse to spare the flock (Acts 20:28–29). First Timothy 4:1 warns that some will depart from the faith by devoting themselves to deceitful spirits and demonic teachings.

This is an uncomfortable reality, but it should not surprise us. Christians encounter competing denominations, traditions, and doctrinal claims. Disputes among Protestants and Roman Catholics, Reformed and Arminian Christians, Baptists, and other traditions can become confusing. The Roman Catholic Church is among the largest bodies in professing Christendom, yet from our Reformed perspective its official teaching presents a false gospel and the church must be regarded as either false or, at minimum, deeply corrupt. The scale of error and corruption within professing Christendom may shock us.

Yet Jesus told us to expect false prophets, false gospels, and corrupt churches. This does not make error harmless, but it keeps us from concluding that the existence of widespread error disproves Christ’s promises. He warned his church in advance.

The Character of False Teachers

False prophets appear to be genuine Christians. They use Christ’s name and say, “Lord, Lord.” They may even claim prophecy, exorcisms, and mighty works performed in his name.

Inwardly, however, they are ravenous wolves. The word ravenous conveys the idea of predatory destruction. False teachers do not care for the flock but use it for personal advantage. Second Peter 2:3 says, “In their greed they will exploit you with false words.”

True ministers follow Christ, the great Shepherd, and care for God’s flock. First Peter 5 teaches them to serve neither for shameful gain nor by domineering over those entrusted to them, but by becoming examples to the flock. False shepherds exploit; true shepherds serve.

You Will Recognize Them by Their Fruit

Jesus repeats this principle twice: “You will recognize them by their fruits” (Matt. 7:16, 20). A true minister does not merely profess Christ and the gospel. His life should display the gospel’s transforming power.

Bad Fruit

Jesus identifies bad fruit in verse 23 when he calls false professors “workers of lawlessness.” Their conduct contradicts God’s commandments.

Matthew 5:21–48 supplies examples. They murder in the heart through anger and contempt. They commit adultery, whether outwardly or through lust. They dishonor marriage through easy divorce, break their word through deception, and maintain unforgiving and vengeful spirits. These deeds of the flesh flow naturally from fallen human nature.

Good Fruit

Good fruit is the kingdom righteousness Jesus describes throughout the Sermon on the Mount. Verse 21 calls it doing the will of the Father. Matthew 5:19 commends those who uphold God’s commandments by their teaching and example rather than relaxing them.

Such fruit flows naturally from the regenerate person, the new person in Christ. Although the immediate issue is recognizing true and false teachers, Jesus extends the principle to all professing Christians: “Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven, but the one who does the will of my Father.”

Doing the Father’s will begins with believing in Christ and entering the gate through faith. Obedience then follows as faith’s fruit.

Two Kinds of Trees

According to Jesus, there are only two kinds of trees: those rooted in fallen Adam and those rooted in Christ. We need do nothing to become the first kind, for all people are born fallen in Adam.

To become a good tree, we must be grafted into Christ. The Spirit works through the gospel to create faith, unite us to Christ, and give us a new heart and nature. Heidelberg Catechism question 20 asks, “Are all people then saved through Christ just as they were lost through Adam?” It answers, “No. Only those are saved who through true faith are grafted into Christ and accept all his benefits.”

The text teaches two complementary truths: good fruit is inevitable for those grafted into Christ, and good fruit is impossible for those who remain apart from him. Both must be held together. Emphasizing only the first may turn the sermon into a demand for fruit that neglects union with Christ. Emphasizing only the second may obscure the transforming power of grace.

The Inevitability of Good Fruit

Jesus says, “Every healthy tree bears good fruit.” The word every matters. Good fruit inevitably follows saving union with Christ. The Catechism expresses the same truth in question 64: “It is impossible for those grafted into Christ by true faith not to produce fruits of gratitude.”

Verse 18 intensifies the statement: “A healthy tree cannot bear bad fruit.” This does not mean that Christians achieve sinless perfection. First John holds together both truths. First John 3:9 says that no one born of God “makes a practice of sinning,” while 1 John 1:8 says, “If we say we have no sin, we deceive ourselves.” John also assures believers who sin that “we have an advocate with the Father, Jesus Christ the righteous.”

A healthy tree cannot bear bad fruit in the sense that a regenerate person cannot continue in unrepentant sin without concern. Christians still sin and fall short, but the Spirit produces grief over sin, confession, repentance, and a desire for obedience.

Repentance itself is good fruit. So are sorrow for sin, the desire for holiness, and the struggle against sinful desires. Those genuinely united to Christ will not remain indifferent to the grief their sin causes the Lord.

This doctrine is important, and a teacher who denies the necessary fruit of faith distorts the gospel. Yet it can be preached so one-sidedly that believers lose assurance while examining whether they have produced enough fruit. Jesus also teaches the complementary truth.

The Impossibility of Good Fruit Apart from Christ

Verse 18 says, “Nor can a diseased tree bear good fruit.” Those not savingly joined to Christ cannot produce kingdom righteousness. Anyone who attempts to apply the Sermon on the Mount apart from union with Christ will fail.

The warning that fruitless trees will be cut down and thrown into the fire may lead someone to say, “I must immediately get to work producing good fruit.” Yet that reverses Jesus’ order. Fruit cannot make a diseased tree healthy. The tree must first be made alive in Christ.

John 15 develops the image: “Abide in me, and I in you. As the branch cannot bear fruit by itself, unless it abides in the vine, neither can you, unless you abide in me.” Jesus continues, “I am the vine; you are the branches. Whoever abides in me and I in him, he it is that bears much fruit, for apart from me you can do nothing.”

Jesus certainly commands his disciples to keep his commandments. Yet before commanding fruit, he calls them to abide in him. We abide through renewed acts of faith: resting in Christ, communing with him in prayer, worshiping him, receiving the means of grace, allowing his words to remain in us, and loving Christ and his teaching.

All who are united to Christ and abide in him will produce fruit. Its inevitability arises from union with Christ, while its impossibility apart from Christ exposes every attempt at self-generated righteousness.

A Transformed Heart

The human will does not swing freely between good and evil without reference to the heart. Moral choices flow from what we are. A heart enslaved to sin produces sinful actions. For the will to move toward obedience, the heart must be renewed.

God alone accomplishes this transformation. The Spirit changes us, creates faith, and unites us to Christ so that we abide as branches in the vine. Jesus states the principle without qualification: “Apart from me you can do nothing.”

Attempting to produce fruit in our own strength resembles buying plastic fruit from a hardware store and stapling it to a dead tree. It may imitate real fruit temporarily, but it remains lifeless and eventually falls away.

At the judgment, some will point to impressive deeds performed in Christ’s name. Jesus will answer, “I never knew you.” Their works did not arise from a saving relationship with him or from hearts transformed by grace.

Jesus therefore calls us first to Christ: trust him, remain rooted in him, love him, and then bear fruit that honors him. John 15:8 says, “By this my Father is glorified, that you bear much fruit and so prove to be my disciples.” The fruit glorifies God because it displays the gospel’s power rather than human self-sufficiency.

Fruit That Flows from Grace

We are not accepted before God because of our fruit or obedience. Even Spirit-produced obedience does not constitute our righteousness before him. Our acceptance rests upon Christ’s righteousness—his perfect obedience and atoning death.

Yet Christ does not leave his people merely forgiven and unchanged. He gives us joy in forgiveness, and the strength of that gospel reality produces grateful obedience. The resulting fruit displays the gospel’s power and brings glory to Christ.

Faith enters through the narrow gate. Union with Christ makes the tree healthy. Abiding in Christ nourishes the branches. Good fruit then follows—not as the basis of our acceptance, but as the inevitable fruit of grace.