They went out from us [seeming at first to be Christians], but they were not really of us [because they were not truly born again and spiritually transformed]; for if they had been of us, they would have remained with us; but they went out [teaching false doctrine], so that it would be clearly shown that none of them are of us.

These things I have written to you with reference to those who are trying to deceive you [seducing you and leading you away from the truth and sound doctrine].

and every spirit that does not confess Jesus [acknowledging that He has come in the flesh, but would deny any of the Son’s true nature] is not of God; this is the spirit of the antichrist, which you have heard is coming, and is now already in the world.

Little children (believers, dear ones), guard yourselves from idols—[false teachings, moral compromises, and anything that would take God’s place in your heart].