Near the end of His Sermon on the Mount, Jesus issued this stark warning to His listeners: “Beware of the false prophets, who come to you in sheep’s clothing, but inwardly are ravenous wolves” (Matthew 7:15).

False prophets were not new to Israel. As long as God has had true prophets, Satan has had false ones. They are seen from the earliest times of redemptive history. Moses warned:

If a prophet or a dreamer of dreams arises among you and gives you a sign or a wonder, and the sign or the wonder comes true, concerning which he spoke to you, saying, “Let us go after other gods (whom you have not known) and let us serve them,” you shall not listen to the words of that prophet or that dreamer of dreams; for the Lord your God is testing you to find out if you love the Lord your God with all your heart and with all your soul. You shall follow the Lord your God and fear Him; and you shall keep His commandments, listen to His voice, serve Him, and cling to Him. But that prophet or that dreamer of dreams shall be put to death, because he has counseled rebellion against the Lord your God. (Deuteronomy 13:1–5)

Elsewhere in the Old Testament, God told the prophet Jeremiah:

The prophets are prophesying falsehood in My name. I have neither sent them nor commanded them nor spoken to them; they are prophesying to you a false vision, divination, futility and the deception of their own minds. (Jeremiah 14:14)

At times, the Lord would judge His people through false prophets. He warned the prophet Zechariah:

For behold, I am going to raise up a shepherd in the land who will not care for the perishing, seek the scattered, heal the broken, or sustain the one standing, but will devour the flesh of the fat sheep and tear off the hoofs. (Zechariah 11:16)

Paul warned the Roman believers: “Now I urge you, brethren, keep your eye on those who cause dissensions and hindrances contrary to the teaching which you learned, and turn away from them. For such men are slaves, not of our Lord Christ but of their own appetites; and by their smooth and flattering speech they deceive the hearts of the unsuspecting” (Romans 16:17–18).

In other parts of the New Testament false prophets are spoken of as “deceitful spirits” who advocate “doctrines of demons” (1 Timothy 4:1) and as those “who will secretly introduce destructive heresies, even denying the Master who bought them” (2 Peter 2:1).

They are called false brothers (2 Corinthians 11:26); false apostles (2 Corinthians 11:13); false teachers (2 Peter 2:1); false speakers, that is, liars (1 Timothy 4:2); and false Christs (Matthew 24:24). The apostle John tells us, therefore, “Beloved, do not believe every spirit, but test the spirits to see whether they are from God, because many false prophets have gone out into the world” (1 John 4:1).

Paul’s last words to the Ephesian elders, when he met with them for a farewell on the beach near Miletus, included a somber warning about inevitable false teachers. “I know that after my departure savage wolves will come in among you, not sparing the flock; and from among your own selves men will arise, speaking perverse things, to draw away the disciples after them. Therefore be on the alert” (Acts 20:29–31).

Those warnings are summarized in the word translated beware in Matthew 7:15. It is not a call simply to notice or sense something, but to be on guard against it because it is so harmful. The word conveys the idea of holding the mind away. False prophets are more than wrong; they are dangerous, and we should not expose our minds to them. They pervert thinking and poison the soul. False prophets are spiritual beasts and are immeasurably more deadly than the physical ones. Both Peter and Jude call them “unreasoning animals” (2 Peter 2:12; cf. Jude 10).

In Palestine, wolves were the most common natural enemy of sheep. They roamed the hills and valleys, looking for a sheep that strayed away from the flock or lagged behind. When a wolf found such a sheep it quickly attacked and tore it to pieces. Even a grown, healthy sheep was utterly defenseless against a wolf.

Wolves are known for being merciless and ferocious (cf. Ezekiel 22:27). The Greek word harpax (ravenous) is also translated “swindler” (Luke 18:11; 1 Corinthians 5:10–11; 6:10), referring metaphorically to those who deceitfully and mercilessly ravage a person of his money and possessions. False prophets and wolves are clever and wily, and are always on the lookout for new victims.

Next time, we’ll look at what God’s Word says about identifying them.

(Adapted from The MacArthur New Testament Commentary: Matthew 1-7.)