1 John 4:3

and every spirit that does not confess Jesus is not from God. This is the spirit of the antichrist, which you have heard is coming and which is already in the world at this time.

And 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.