We can identify a false teacher or a false prophet by examining first and foremost their teaching and secondly their behavior in light of Scripture. If what they are teaching is not consistent with what the Holy Spirit has plainly revealed in Scripture, they are a false teacher and are to be ignored, even if they live extraordinary lives, even if they appear to have supernatural insight, or even if they seem to work great miracles. Jesus warned us that there would be false prophets who would perform great signs and would seek to lead astray, if possible, even the elect (Matthew 24:24, Mark 13:22). It is, therefore, urgent not to be distracted by such things, but to focus on the content of their teaching. Our Lord explained:

“Beware of the false prophets, who come to you in sheep’s clothing, but inwardly are ravenous wolves. You will know them by their fruits. Grapes are not gathered from thorn bushes nor figs from thistles, are they? So every good tree bears good fruit, but the bad tree bears bad fruit. A good tree cannot produce bad fruit, nor can a bad tree produce good fruit. Every tree that does not bear good fruit is cut down and thrown into the fire. So then, you will know them by their fruits,” (Matthew 7:15-20).

Be careful to note the analogies used here. The false prophet comes in the clothing of a sheep but is inwardly a wolf. He appears on the outside as a sheep but is secretly a wolf within. We are to know them by their “fruit,” not by their “clothing.” A fig tree bears figs, an apple tree bears apples, a prophet bears prophesy, and a teacher bears teaching. Pay attention to how Luke’s Gospel communicates the same teaching of Jesus:

“For there is no good tree which produces bad fruit, nor, on the other hand, a bad tree which produces good fruit. For each tree is known by its own fruit. For men do not gather figs from thorns, nor do they pick grapes from a briar bush. The good man out of the good treasure of his heart brings forth what is good; and the evil man out of the evil treasure brings forth what is evil; for his mouth speaks from that which fills his heart,” (Luke 6:43-45).

While his behavior and outward appearances might be merely sheep’s clothing, hiding the wolf underneath, and while he might seem like a great guy, the words he says and the message he brings will find him out. Jesus warned us, “Beware!” we are to be vigilantly on guard against this. False teachers will often even point to this very passage and argue that you can “know them by their fruit,” and then point out the great charity work they are involved in and their clean, tidy, seemingly moral lives. They will say, “look at the fruit!” while they are pointing at their deceptive outward clothing. That is not what Jesus says the fruit is. “For his mouth speaks from that which fills his heart.” His words are the window into what is underneath the polished exterior. Jesus said this elsewhere, saying:

“Either make the tree good and its fruit good, or make the tree bad and its fruit bad; for the tree is known by its fruit. You brood of vipers, how can you, being evil, speak what is good? For the mouth speaks out of that which fills the heart,” (Matthew 12:33-34).

He likewise said of the false teachers of his day:

“Woe to you, scribes and Pharisees, hypocrites! For you are like whitewashed tombs which on the outside appear beautiful, but inside they are full of dead men’s bones and all uncleanness,” (Matthew 23:27).

“Woe to you! For you are like concealed tombs, and the people who walk over them are unaware of it,” (Luke 11:44).

The image here, drawing from the Old Testament ceremonial purity laws, is of something that looks innocuous or even pleasing on the outside, but is not only corrupt within but also makes the unsuspecting impure because of its deception. It is, therefore, imperative that we not be distracted by any outward appearance of “goodness,” but rather focus first and foremost on the window we have to what is within: the words.

It is no surprise, then, that in one of the earliest church writings outside the New Testament we possess, called the Didache, in Chapter 11 which specifically discusses how to identify false prophets and false teachers, the very first instruction before all others is:

“Whosoever, therefore, shall come and teach you all these things that have been said before, receive him; but if the teacher himself be perverted and teach a different doctrine to the destruction thereof, hear him not.”

So we are to judge a teacher today by what our Lord and His apostles and prophets taught. Just as Paul also warned:

“But even if we, or an angel from heaven, should preach to you a gospel contrary to what we have preached to you, he is to be accursed! As we have said before, so I say again now, if any man is preaching to you a gospel contrary to what you received, he is to be accursed!” (Galatians 1:8-9).gospel

The Bible does provide us some concrete examples:

• False teachers will often seek to add to the work of Christ some law, work, ritual, or ordinance that a believer must also perform in addition to repentance and faith in Christ, saying that this too must be done to be saved, (Galatians 3,  1 Timothy 4:1-5).
• On the other hand, many false teachers will do the opposite, proclaiming that, because God is so merciful and salvation is by grace alone, you, therefore, don’t need to repent at all. They pervert God’s grace and make it a license to sin, (Jude 4).
• Any teacher who subtly denies Jesus (2 Peter 2:1), or His authority (Jude 4), or His deity (1 Corinthians 12:2-3), or that He came down from heaven and took on human flesh and died in our place (1 John 1:1-3), these are clearly false teachers.

These are just some of the various ways false teaching has attempted to pervert and undermine the gospel from the very beginning. These and other things like them are things against which we need to be on guard.

A false teacher will also often display a profit motive. 2 Peter 2:3 says:

“their greed will exploit you with false words.”

And Jude 11 that:

“For pay, they have rushed headlong into the error of Balaam.”

Early Christians took these biblical warnings to heart, as testified again in the Didache, which preserves a warning in Chapter 11 verse 12:

“Whosoever shall say in the Spirit, ‘Give me silver’ or anything else, ye shall not listen to him.”

This is not true of all false teachers, and again some will point to acts of apparent charity and generosity which are the sheep’s clothing they use to distract us from their false teaching, but if anyone is seeking to make themselves rich on their so-called ministry, or who is claiming a word from God that you must give them your money or possessions, or who promises God’s blessing on you if you will pay them money, this person is a false teacher.

We would also be remiss if we did not mention the oldest test in all of Scripture. If one predicts a future event in the name of God and it doesn’t come to pass, or if they lead you to worship any god other than the true God of Scripture, they are a false prophet, (Deuteronomy 18:20-22, Deuteronomy 13:1-4).

All of these examples in Scripture are important indicators of many of the sorts of things for which to look. We must always be on our guard, know the scriptures and the gospel thoroughly, and meditate on them often. We must be diligent to see through the facade and to address what is actually being said, not merely the way it is said or the often deceptive outer details of the person saying it. The externals do, however, matter when they are negative. A person speaking the truth but not living in light of it is a hypocrite and a liar and ought not to be trusted. The qualified elder and overseer of God’s people will be a man defined by Godly character (Titus 1:6-9, 1 Timothy 3).