1 John 4:1-3

Amplified Bible

Testing the Spirits

4 Beloved, do not believe every spirit [speaking through a self-proclaimed prophet]; instead test the spirits to see whether they are from God, because many false prophets and teachers have gone out into the world. ² By this you know and recognize the Spirit of God: every spirit that acknowledges and confesses [the fact] that Jesus Christ has [actually] come in the flesh [as a man] is from God [God is its source]; ³ and every spirit that does not confess Jesus [acknowledging that He has come in the flesh, but would deny any of the Son’s true nature] is not of God; this is the spirit of the antichrist, which you have heard is coming, and is now already in the world.