Matthew Henry Commentary 1 John 2:18-23

"Little children, it is the last hour: and as ye heard that antichrist cometh, even now have there arisen many antichrists; whereby we know that it is the last hour. They went out from us, but they were not of us; for if they had been of us, they would have continued with us: but [they went out], that they might be made manifest that they all are not of us. And ye have an anointing from the Holy One, and ye know all the things. I have not written unto you because ye know not the truth, but because ye know it, and because no lie is of the truth. Who is the liar but he that denieth that Jesus is the Christ? This is the antichrist, [even] he that denieth the Father and the Son. Whosoever denieth the Son, the same hath not the Father: he that confesseth the Son hath the Father also." — 1 John 2:18-23 (ASV)

Every person is an antichrist who denies the Person, or any of the offices of Christ; and in denying the Son, they deny the Father also, and have no part in His favor while they reject His great salvation. Let this prophecy, that seducers would rise in the Christian world, keep us from being seduced. The church does not know well who its true members are and who are not; but in this way, true Christians were tested and made more watchful and humble.

True Christians are anointed ones; their name 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 are usually falsehoods and errors relating to the person of Christ. The anointing from the Holy One, alone, can keep us from delusions. While we judge favorably of all who trust in Christ as the Divine Savior, 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 Spirit. Let us protest against such antichristian doctrine and keep from them as much as we can.