18 Dear children, the last hour is here. You have heard that the Antichrist is coming, and already many such antichrists have appeared. From this we know that the last hour has come. 19 These people left our churches, but they never really belonged with us; otherwise they would have stayed with us. When they left, it proved that they did not belong with us.
20 But you are not like that, for the Holy One has given you his Spirit, and all of you know the truth. 21 So I am writing to you not because you don't know the truth but because you know the difference between truth and lies. 22 And who is a liar? Anyone who says that Jesus is not the Christ. Anyone who denies the Father and the Son is an antichrist. 23 Anyone who denies the Son doesn't have the Father, either. But anyone who acknowledges the Son has the Father also.
Matthew Henry's Commentary on 1 John 2:18-23
Commentary on 1 John 2:18-23
(Read 1 John 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.