The Bible explains how we can, "False prophets are people who prophesy or say things in God’s name - as if it were His very Words. We can know them by testing what they are saying or teaching, if these things actually take place or comes true. If what they say does not come true then such people are the false prophets as determined by God” - Deut. 18:20-22.
If you don’t believe in God or His recorded word, or His saving gospel of the water and the Spirit, then you are still blind and defiled having no way of knowing who is who. Anything you might say against this truth only heaps up the wrath of God upon your hairy head. So, it will be better to read, come to know yourself properly, and to repent before God.
The doomsday prophets, for example, give exact dates and times the world will end, and, famous TV Evangelists claim they can heal people from their illnesses and death diseases are all proved false…to name a few of them.
Furthermore, Christians who say Christ' blood on the Cross ALONE cleanses them from all sin, and later find out that all their sin still remain intact in their hearts and are unchanged; then these kinds of pastors that taught them are indeed the false prophets. What they say in God’s name has not taken place, for what they taught could not change sinners into saints, and unable to resolve the sin problem once and for all.
All these pastors can be tested under the microscope of God’s Word as to what they preach and teach. If what they say does not come true then such pastors are the false prophets - as determined by God.
However, on the other hand, if a truly born again preacher who is filled with God’s Holy Spirit (a true man of God) says the gospel of the water and the Spirit blots out all our sin if we understand and believe in it 100% - John 3:5. Then we can test what they say is true. If the people are born again by believing in this true gospel from heaven testify that they have no more sin in their hearts having a clear conscience, and never say their miserable repentance prayers again, then these preachers are not false prophets. What they say has indeed come true. Jesus said, ‘We can know them by their fruit.”
So, we have these two kinds of Christian pastors in the world today, one the false prophets, and the other the genuine prophets of God. Sadly, the former are in greater numbers spreading the devils lies.This was the reason why Matthew 7:20-23 was recorded in the Bible.
Many believers will never be entering this holy place, called Heaven, for they had ears but refused to listen, and had eyes, but refused to read.