1 John 4:1-3

Darby Translation

4 Beloved, believe not every spirit, but prove the spirits, if they are of God; because many false prophets are gone out into the world.

² Hereby ye know the Spirit of God: every spirit which confesses Jesus Christ come in flesh is of God;

³ and every spirit which does not confess Jesus Christ come in flesh is not of God: and this is that [power] of the antichrist, [of] which ye have heard that it comes, and now it is already in the world.