1John 4:1-3

Testing the Spirits 1Beloved, do not believe every spirit, but test the spirits to see whether they are from God; for many false prophets have gone out into the world.2By this you know the Spirit of God: every spirit that confesses that Jesus Christ has come in the flesh is from God,3and every spirit that does not confess Jesus is not from God. And this is the spirit of the antichrist, of which you have heard that it is coming; and now it is already in the world.