Matthew 7:15 - Meaning and Application

Here is a warning against false prophets, that we must not be fooled or led astray by them. A prophet is properly someone who foretells future events. In the Old Testament, some people claimed to speak for God without any warrant, and events proved them wrong, like Zedekiah in (1 Kings 22:11) and another Zedekiah in (Jeremiah 29:21). But prophets also taught people their duty, so false prophets here are false teachers.

Christ himself is a Prophet and Teacher sent from God, and he planned to send teachers under his authority. So he warns everyone to watch out for counterfeits. These people claim they will heal souls with sound teaching, but instead they poison them. They are false teachers and false prophets in two ways. First, they give false credentials. They claim direct authority and inspiration from God when they have none. Even if some of what they say is true, we should still beware of them as false prophets. False apostles are people who say they are apostles and are not (Revelation 2:2), and false prophets are like that. Take care with anyone who claims revelation. Do not accept them without solid proof, because one foolish step can open the door to many more.

Second, they preach false doctrine on the central truths of religion. They teach what goes against the truth that is in Jesus, the truth that leads to godly living. The first kind of false prophet is one who pretends to speak for God. The second kind usually goes with it, because who would display false colors except to hide their real purpose and attack the truth more effectively? So beware of them, suspect them, test them, and once you see their falsehood, avoid them. Have nothing to do with them. Stay on guard against this temptation, which often appears when reform is advancing and divine light is growing stronger. When God’s work is revived, Satan and his helpers are especially active.

There is a good reason for this warning: they are wolves in sheep’s clothing (Matthew 7:15). We must be careful, because their claims are attractive and likely to deceive us if we are not watchful. They come in sheep’s clothing, wearing the outward dress of prophets, plain and rough, like the garment used to deceive in (Zechariah 13:4). Elijah’s mantle was called a sheep-skin cloak by the Septuagint. So we must not be taken in by a person’s clothing or outward style, like the scribes who liked to walk in long robes (Luke 20:46).

This also means they only appear to be sheep. Outwardly they seem harmless, gentle, useful, and good, so much so that they seem better than anyone else. They act as if they are righteous people, and because of that clothing, they are welcomed among the sheep. That gives them the chance to do harm before anyone notices. They and their errors are covered with the fake beauty of holiness and devotion. Satan himself disguises himself as an angel of light (2 Corinthians 11:13-14). The enemy has the look of a lamb but is still dangerous (Revelation 13:11). His servants can look human and reasonable on the outside, but still be deceivers (Revelation 9:7-8). Such people speak softly and act smoothly, but their words are slippery and harmful (Romans 16:18; Isaiah 30:10).

Their outward show is deceptive, and their inward purpose is evil. Inside, they are ravening wolves. Every hypocrite is a goat in sheep’s clothing, not a sheep at all, but the worst enemy sheep can have. They come only to tear, devour, scatter the flock, and drive people away from God and from one another into crooked paths (John 10:12). Anyone who wants to steal truth from us and fill us with error means harm to our souls, whatever they say. Paul calls them grievous wolves (Acts 20:29). They feed on themselves, serve their own appetites (Romans 16:18), and treat people as prey, using them for gain. Since it is so easy to be deceived, and so dangerous to be deceived, beware of false prophets.

There is also a good rule to guide this warning: we must test everything (1 Thessalonians 5:21), and try the spirits (1 John 4:1). Here Christ gives us a clear test: you will know them by their fruits (Matthew 7:16-20). Fruit reveals the tree. You cannot always tell by the bark, the leaves, or the spread of the branches, but you can tell by the fruit. Fruit matches the nature of the tree. People may, in their words, force themselves to act against their true nature, but their lives and habits will usually match what they truly are.

If you know the tree, you know what kind of fruit to expect. You do not look for grapes on thorn bushes or figs on thistles, because that is against their nature. A thorn might have an apple stuck on it, or a bunch of grapes may hang there, but that fruit did not grow from the thorn. In the same way, corrupt and unsanctified hearts are like thorns and thistles. They came in with sin, are worthless, trouble others, and are fit only for the fire in the end. Good works are good fruit, like grapes and figs. They please God and help people. But good fruit is never to be expected from bad people, any more than a clean thing can come from what is unclean. They do not have the inward principle that produces what is acceptable to God. From an evil treasure, evil things will come out.

On the other hand, if you know the fruit, you can tell what kind of tree it is. A good tree cannot produce evil fruit, and a bad tree cannot produce good fruit. In fact, it cannot help but bring forth evil fruit. Still, the fruit of the tree is the fruit it brings forth naturally, openly, often, and consistently, which is its real output. People are known not by one or two acts, but by the course and pattern of their lives, especially by the acts they do most often, and especially those that seem most free and truly their own. The main thing is their usual walk, not occasional appearances.

The doom of barren trees is certain: they will be cut down and thrown into the fire. God will deal with them as people deal with dry trees that only clutter the ground. He will show clear signs of displeasure, strip them of their gifts and abilities, cut them down by death, and cast them into the fire of hell, a fire stoked by God's wrath and fed with the wood of fruitless trees. Compare this with (Ezekiel 31:12-13), (Daniel 4:14), and (John 15:6).

The way to test false teachers is by their fruits, as Christ says, "You will know them by their fruits." First, look at the fruit of their lives, their words, actions, and whole way of living. If you want to know whether they are sound or false, watch how they live, because their works will speak for or against them. The scribes and Pharisees, Jewish law teachers, sat in Moses' seat and taught the law, but they were proud, greedy, false, and harsh. That is why Christ warned his disciples to beware of them and their teaching, like leaven that spreads through dough (Mark 12:38).

If people claim to be prophets but live in sin, that proves their claims false. Those who have their belly as their god and set their minds on earthly things are no true friends of Christ's cross, whatever they say (Philippians 3:18-19). Those are not taught or sent by the holy God whose lives show that they are led by an unclean spirit. God may place treasure in earthen vessels, that is, weak human lives, but not in corrupt vessels like these. They may speak God's statutes, but what right do they have to declare them?

Second, test them by the fruit of their doctrine, the teaching they give as prophets. This is not the only test, but it is one good way to judge whether a doctrine comes from God. Ask what it leads people toward. What desires and actions does it produce in those who accept it? If the teaching is from God, it will lead to serious devotion, humility, love, charity, holiness, and other Christian graces. But if the teaching clearly makes people proud, worldly, quarrelsome, loose in conduct, unjust, unkind, or a source of division and public disorder, then we may conclude that this persuasion does not come from God, who calls us (Galatians 5:8). This wisdom is from above, while the other kind is earthly and harmful (James 3:15). Faith and a good conscience belong together (1 Timothy 1:19; 1 Timothy 3:9).

So, teachings that are up for debate should be tested by the graces and duties that are plainly required. Any view that leads to sin does not come from God. But if we cannot judge them by their fruit, we must turn to the great test, the law and the testimony, and ask whether they speak according to that rule.