1 John 4:1-3

Young's Literal Translation

4 Beloved, every spirit believe not, but prove the spirits, if of God they are, because many false prophets have gone forth to the world;

² in this know ye the Spirit of God; every spirit that doth confess Jesus Christ in the flesh having come, of God it is,

³ and every spirit that doth not confess Jesus Christ in the flesh having come, of God it is not; and this is that of the antichrist, which ye heard that it doth come, and now in the world it is already.