“Hereby know ye the spirit of God: euery spirit that confesseth that Iesus Christ is come in the flesh, is of God.”
1611 King James Version (KJV)
4:2 Every spirit - Or teacher. Which confesseth - Both with heart and voice. Jesus Christ, who is come in the flesh, is of God - This his coming presupposes, contains, and draws after it, the whole doctrine of Christ.
1Jo 4:2 Every spirit that confesseth that Jesus Christ is come . . . is of God. He who confesses from the heart that Christ has come in the flesh shows that he has the Spirit of God. In the flesh. One of the heresies was that Christ had come but that there had been no incarnation.