1 John 4:2-3

This is how we know if they have the Spirit of God: If a person claiming to be a prophet acknowledges that Jesus Christ came in a real body, that person has the Spirit of God. But if someone claims to be a prophet and does not acknowledge the truth about Jesus, that person is not from God. Such a person has the spirit of the Antichrist, which you heard is coming into the world and indeed is already here.