What the Bible says about false prophets : 1 John 4:1 Beloved, believe not every spirit, but try the spirits whether they are of God: because many false prophets are gone out into the world.Hereby know ye the Spirit of God: Every spirit that confesseth that Jesus Christ is come in the flesh is of God: 3and every spirit that confesseth not that Jesus Christ is come in the flesh is not of God: and this is that spirit of antichrist, whereof ye have heard that it should come; and even now already is it in the world.

4Ye are of God, little children, and have overcome them: because greater is he that is in you, than he that is in the world. 5They are of the world: therefore speak they of the world, and the world heareth them. 6We are of God: he that knoweth God heareth us; he that is not of God heareth not us. Hereby know we the spirit of truth, and the spirit of error.

2 Peter 2:1 But there were false prophets also among the people, even as there shall be false teachers among you, who privily shall bring in damnable heresies, even denying the Lord that bought them, and bring upon themselves swift destruction.

Revelation 20:10 And the devil that deceived them was cast into the lake of fire and brimstone, where the beast and the false prophet are, and shall be tormented day and night for ever and ever.

Matthew 7:15 Beware of false prophets, which come to you in sheep's clothing, but inwardly they are ravening wolves.Ye shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles? 17Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit. 18A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit. 19Every tree that bringeth not forth good fruit is hewn down, and cast into the fire. 20Wherefore by their fruits ye shall know them.

21 Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven. 22Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works? 23And then will I profess unto them, I never knew you: depart from me, ye that work iniquity.

24 Therefore whosoever heareth these sayings of mine, and doeth them, I will liken him unto a wise man, which built his house upon a rock: 25and the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell not: for it was founded upon a rock. 26And every one that heareth these sayings of mine, and doeth them not, shall be likened unto a foolish man, which built his house upon the sand: 27and the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell: and great was the fall of it.