Q. Based on your last article about false prophecy, how can you tell whether someone is a false prophet?

A. The basic sign of a false prophet is that his word will go against the Word of God. But, that is also where the problem lies because many people do not know the Word of God correctly and have never been taught the Scriptures so they don't know enough to test the words of a so-called prophecy. But, it is possible to know the Scriptures and to be taught correctly so it is on that basis that I will proceed with how it is done .I'm going to use several Scriptures as my basis and so let's start. There are basically two things that will tell if a person is a false prophet. First, does his word contradict the Scriptures and secondly if his predictions come true or not. So, let's look at the first test, whether his word contradicts the Scriptures. Deut 13.1-5 says " If a prophet or a dreamer of dreams arises among you and gives you a sign or a wonder and the sign or 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 word of that prophet or that dreamer of dreams; for the Lord your God is testing (examining) 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 who brought you from the land of Egypt and redeemed you from the house of slavery, to seduce you from the way in which the Lord your God commanded you to walk. So you shall purge the evil from among you."
In this passage, the Lord is saying that if a prophet or a dreamer comes forward with a word to depart from the ways of God (v5) and shows a sign or a wonder, you are not to listen to what he says. In fact, God will cause this to happen to test you to see if you will follow the sign or wonder, or follow the Word of God. You do not follow anyone or their words if it contradicts the Scriptures, no matter what sign they give. An example of a false prophecy can be found in 1 Kings 13.18. In this passage, God told a prophet to do a certain thing and another prophet came along and told him that God told him that he didn't have to do it. The first prophet was deceived and he died. True prophecy cannot be annulled by another prophet unless the first prophet hears directly from the Lord that it was. Another verse that goes along the same lines can be found in Isa 8.20 where it reads "To the Law (Torah) and to the testimonies (prophets). If they do not speak according to this word it is because they have no light (understanding)." In Acts 17.10-11 it says that the Bereans were "more noble than those in Thessalonica for they received the word (which Paul spoke) with great eagerness, examining daily, to see whether these things were true." They did not rely on some "oral law" passed down from the rabbis but checked the Word of God. And the Word they were checking was the Tanak, or "old" testament. Everything Paul taught was out of the Tanak and it could be verified by the Tanak, and that's what we need to do when confronted with anyone's teaching, check it out. Unfortunately, many have been taught wrong doctrine and that needs to be straightened out before they will be able to test anything.
The second thing used to test a false prophet is whether what they say comes to pass or not. Deut 18. 21-22 says "And you may say in your heart,' how shall we know the word which the Lord has not spoken?' "When a prophet speaks in the name of the Lord, if the thing does not come about or come true, that is the thing which the Lord has not spoken. The prophet has spoken it presumptuously; you shall not be afraid of him." So, if the person prophesies in the name of the Lord and the event does not come true or come about, then he is a false prophet. Now, notice he does it "in the name of the Lord" and that is important. Nobody has all the answers and we see through a glass dimly so we aren't always right about some of our interpretations, but that doesn't make us a false prophet. A false prophet will say that the "Lord has shown me", or has "told me to say" something and if it isn't true, then he is false. Yeshua had these things in mind when he discussed false prophets in Mt 17.10-11 where he says "Beware of the false prophets who come to you in sheep's clothing, but inwardly are ravenous wolves. You shall know them by their fruits . Grapes are not gathered from thorn bushes, nor figs from thistles, are they? Even so, every good tree bears good fruit; but a rotten tree bears bad fruit. A good tree cannot produce bad fruit, nor can a rotten 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" What Yeshua is saying here is that a tree is a person and the fruit is their doctrine. A good tree, or a believer, will have sound doctrine and an unbeliever will have corrupt doctrine. So, how can you know? You have to test their doctrines by the Scriptures. External works is not really the intent of "fruits" here otherwise a false prophet can appear righteous outwardly. But the true prophet will be true to the Word of God and a false prophet can't.
In conclusion, there are two tests for a false prophet. First, check to see if what they say lines up with the Word of God (Deut 13.1-5; Isa 8.20) no matter what sign or wonders happens to occur. Remember, the false prophet may perform many signs and wonders but he wants you to follow the sign and not the Word of God. Secondly, if a person makes a prediction in the name of the Lord and it does not come to pass, then the Lord did not speak. So, in short, check what a person says by the Word of God and disregard any signs or wonders. A sign or a wonder just calls attention to what the person is saying and check the event, if it occurs or not. These are two basic ways to test for false prophets.