The Sermon on the Mount · Matthew 7:15-20

By Their Fruits: Ye Shall Know Them

Matthew 5 to 7 · Jesus’ greatest sermon, the manifesto of the kingdom

Jesus warns His followers to beware of false prophets, who come in sheep's clothing but are inwardly ravening wolves. The test He gives is not their words or their appearance but their fruit: a good tree brings forth good fruit, and a corrupt tree evil fruit. What a life and a teaching actually produce over time reveals what they truly are.

Beware of false prophets, which come to you in sheep’s clothing, but inwardly they are ravening wolves. Ye shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles? Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit. A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit. Every tree that bringeth not forth good fruit is hewn down, and cast into the fire. Wherefore by their fruits ye shall know them.Matthew 7:15-20 (KJV)

What Jesus said

Beware of false prophets, which come to you in sheep's clothing, but inwardly they are ravening wolves. The danger is disguise; the wolf looks like a sheep. So how are they known? Ye shall know them by their fruits, Jesus says. Do men gather grapes of thorns or figs of thistles? The nature of the tree shows in what it produces.

Every good tree brings forth good fruit, and a corrupt tree cannot bring forth good fruit. In time, what is rotten will reveal itself, and every tree that does not bear good fruit is cut down and burned. Wherefore, He concludes, by their fruits ye shall know them. The test is patient observation of the harvest, not first impressions.

What it meant then, and what it means now

Israel had a long memory of false prophets who told the people what they wanted to hear. Jesus warns that such deceivers will keep coming, dressed convincingly in the costume of true religion. Their threat is precisely that they do not look dangerous, which is why fruit, not appearance, must be the test.

The warning is timeless. Teachers, leaders, and movements still present themselves in sheep's clothing, and the loudest or most impressive voice is not always the truest. Jesus gives His followers a discerning realism: watch the fruit. Look at the character produced, the lives shaped, the honesty and love or the corruption and self-interest that a teaching actually yields over time.

How it goes to the heart

Fruit is not merely outward success or crowds or eloquence; it is the deep character that a life and a message produce. Jesus is teaching us to look past the packaging to the harvest, and to ask of any teacher, and of ourselves, what kind of people this actually makes.

This turns the test back on us as well. We too are trees, and our lives bear fruit that reveals our roots. The point is not anxious self-inspection but honest attention: the heart, whatever it claims, shows itself over time in what it produces. Good fruit grows from being rooted in Christ, not from pretending.

How it has been misapplied, and rightly applied

This passage has been misused to license harsh, suspicious fruit-inspecting of everyone, turning believers into cynics who assume the worst and rush to condemn. But Jesus aimed the warning chiefly at false teachers who lead others astray, and He asks for patient discernment, not paranoia, since fruit takes time to appear.

Rightly applied, it is a gift of protection. It keeps us from being taken in by charisma and spectacle, and it anchors our trust in what is real: the enduring fruit of truth, love, humility, and holiness. It also calls us to examine our own lives with the same honesty, welcoming the work of God that alone makes a tree good.

A closer look at the words

The danger Jesus names is disguise. False prophets come in sheep’s clothing, looking exactly like the flock, but inwardly they are ravening wolves. Their whole threat lies in not looking dangerous, which is why appearance cannot be the test. Israel had a long, painful memory of prophets who told the people what they wanted to hear, and Jesus warns that such deceivers will keep coming.

The test He gives is fruit. Do men gather grapes of thorns, or figs of thistles? A tree’s nature shows in what it produces, and it cannot fake a harvest indefinitely. A good tree brings forth good fruit, and a corrupt tree cannot bring forth good fruit; given time, what is rotten reveals itself. By their fruits ye shall know them.

Fruit here means more than outward success, crowds, or eloquence, which the false can counterfeit for a season. It means the deep character a life and a message actually produce over time, the honesty and love or the corruption and self-interest that eventually become visible in the harvest.

Living this today

Jesus gives His followers a discerning realism. The loudest, most impressive, or most popular voice is not always the truest, and charisma is no proof of character. Watch the fruit: look at the people a teaching shapes, the way a leader treats others, the integrity or its absence that shows up over years, not just in a polished moment.

This is not a license for cynical, suspicious fruit-inspecting of everyone in sight. Jesus aimed the warning chiefly at false teachers who lead others astray, and He asks for patient discernment, not paranoia, since real fruit takes time to appear. Rushing to condemn is its own bad fruit.

The test also turns back on us. We too are trees, and our lives bear fruit that reveals our roots. The point is not anxious self-inspection but honest attention, and the good news is that good fruit is not something we manufacture. It grows from being rooted in Christ, welcoming the work of God that alone can make a tree good.

Two practical safeguards follow. First, give things time; a single impressive sermon or a season of apparent success proves little, while years reveal much. Second, weigh the fruit that truly matters, not crowds or charisma or confidence, but honesty, humility, love, and a life that bends others toward Christ rather than toward the teacher. And when the same test is turned on us, it is not cause for dread but for dependence, since the only way any tree becomes good is by being joined to the One who is Himself the true and living vine.

How it points to Christ

Jesus is the good tree from which all good fruit finally comes. He calls Himself the true vine and tells us that apart from Him we can do nothing, but that those who abide in Him bear much fruit. The good life the sermon describes is not something we manufacture but something that grows from being joined to Him.

He is also the true Prophet in contrast to every false one, the faithful shepherd who lays down His life for the sheep rather than a wolf who devours them. To follow Him is to be grafted into the one root that can make us good, so that the fruit of His Spirit, love, joy, peace, and the rest, begins to appear in lives that could never produce it on their own.

A note for every tradition: the Sermon on the Mount is honored across the whole church as the heart of Jesus’ teaching. This is faithful, mainstream exposition, holding the hard sayings with both honesty and grace. Above all it points to Christ, who alone lived this sermon perfectly and gives grace to all who follow Him.

Continue in the sermon: The narrow gate · The wise and foolish builders · The Beatitudes · The whole Sermon on the Mount