1 John 4:2-3 NAS

2 By this you know the Spirit of God: 1every spirit that 2confesses that 3Jesus Christ has come in the flesh is from God;

References for 1 John 4:2

3 and every spirit that 4does not confess Jesus is not from God; this is the spirit of the 5antichrist, of which you have heard that it is coming, and 6now it is already in the world.

References for 1 John 4:3