2:18-23 Every man is an antichrist, who denies the Person, or any of the offices of Christ; and in denying the Son, he denies the Father also, and has no part in his favour while he rejects his great salvation. Let this prophecy that seducers would rise in the Christian world, keep us from being seduced. The church knows not well who are its true members, and who are not, but thus true Christians were proved, and rendered more watchful and humble. True Christians are anointed ones; their names expresses this: they are anointed with grace, with gifts and spiritual privileges, by the Holy Spirit of grace. The great and most hurtful lies that the father of lies spreads in the world, usually are falsehoods and errors relating to the person of Christ. The unction from the Holy One, alone can keep us from delusions. While we judge favourably of all who trust in Christ as the Divine Saviour, and obey his word, and seek to live in union with them, let us pity and pray for those who deny the Godhead of Christ, or his atonement, and the new-creating work of the Holy Ghost. Let us protest against such antichristian doctrine, and keep from them as much as we may.

19. out from us—from our Christian communion. Not necessarily a formal secession or going out: thus Rome has spiritually gone out, though formally still of the Christian Church.

not of us—by spiritual fellowship (1Jo 1:3). "They are like bad humors in the body of Christ, the Church: when they are vomited out, then the body is relieved; the body of Christ is now still under treatment, and has not yet attained the perfect soundness which it shall have only at the resurrection" [Augustine, Ten Homilies on the First Epistle of John, Homily 3.4].

they would … have continued—implying the indefectibility of grace in the elect. "Where God's call is effectual, there will be sure perseverance" [Calvin]. Still, it is no fatal necessity, but a "voluntary necessity" [Didymus], which causes men to remain, or else go from the body of Christ. "We are either among the members, or else among the bad humors. It is of his own will that each is either an Antichrist, or in Christ" [Augustine]. Still God's actings in eternal election harmonize in a way inexplicable to us, with man's free agency and responsibility. It is men's own evil will that chooses the way to hell; it is God's free and sovereign grace that draws any to Himself and to heaven. To God the latter shall ascribe wholly their salvation from first to last: the former shall reproach themselves alone, and not God's decree, with their condemnation (1Jo 3:9; 5:18).

that they were not all of us—This translation would imply that some of the Antichrists are of us! Translate, therefore, "that all (who are for a time among us) are not of us." Compare 1Co 11:19, "There must be heresies among you, that they which are approved may be made manifest among you." For "were" some of the oldest manuscripts read "are." Such occasions test who are, and who are not, the Lord's people.