1 John 4:2-3 HNV

2 By this you know the Spirit of God: every spirit who confesses that Yeshua the Messiah has come in the flesh is of God,
3 and every spirit who doesn't confess that Yeshua the Messiah has come in the flesh is not of God, and this is the spirit of the anti-messiah, of whom you have heard that it comes. Now it is in the world already.