1 John 2:19

Whom has he called antichrists? He goes on and expounds. "Whereby we know that it is the last hour," By what? Because "many antichrists are come. They went out from us;" see the antichrists! "They went out from us:" therefore we bewail the loss. Hear the consolation. "But they were not of us." All heretics, all schismatics went out from us, that is, they go out from the Church; but they would not go out, if they were of us. Therefore, before they went out they were not of us. If before they went out they were not of us, many are within, are not gone out, but yet are antichrists. We dare to say this: and why, but that each one while he is within may not be an antichrist? For he is about to describe and mark the antichrists, and we shall see them now. And each person ought to question his own conscience, whether he be an antichrist. For antichrist in our tongue means, contrary to Christ. Not, as some take it, that antichrist is to be so called because he is to come ante Christum, before Christ, i.e. Christ to come after him: it does not mean this, neither is it thus written, but Antichristus, i.e. contrary to Christ. Now who is contrary to Christ ye already perceive from the apostle's own exposition, and understand that none can go out but antichrists; whereas those who are not contrary to Christ, can in no wise go out. For he that is not contrary to Christ holds fast in His body, and is counted therewith as a member. The members are never contrary one to another. The entire body consists of all the members.

"They went out from us; but," be not sad, "they were not of us." How provest thou this? If they had been of us, they would doubtless have continued with us. Hence therefore ye may see, that many who are not of us, receive with us the Sacraments, receive with us baptism, receive with us what the faithful know they receive, Benediction, the Eucharist, and whatever there is in Holy Sacraments: the communion of the very altar they receive with us, and are not of us. Temptation proves that they are not of us. When temptation comes to them as if blown by a wind they fly abroad; because they were not grain. But all of them will fly abroad, as we must often tell you, when once the fanning of the Lord's threshing-floor shall begin in the day of judgment. "They went out from us, but they were not of us; if they had been of us, they would no doubt have continued with us." For would ye know, beloved, how most certain this saying is, that they who haply have gone out and return, are not antichrists, are not contrary to Christ? Whoso are not antichrists, it cannot be that they should continue without. But of his own will is each either an antichrist or in Christ. Either we are among the members, or among the bad humors. He that changeth himself for the better, is in the body, a member: but he that continues in his badness, is a bad humor; and when he is gone out, then they who were oppressed will be relieved.

For hear and see. Certainly all who go out from the Church, and are cut off from the unity of the Church, are antichrists; let no man doubt it: for the apostle himself hath marked them, "They went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us." Therefore, whoso continue not with us, but go out from us, it is manifest that they are antichrists.

But let us not be made sad: "They went out from us, but they were not of us for if they had been of us, they would no doubt have continued with us." If then they went out from us, they are antichrists; if they are antichrists, they are liars; if they are liars, they deny that Jesus is the Christ. Once more we come back to the difficulty of the question. Ask them one by one; they confess that Jesus is the Christ. The difficulty that hampers us comes of our taking what is said in the Epistle in too narrow a sense. At any rate ye see the question; this question puts both us and them to a stand, if it be not understood. Either we are antichrists, or they are antichrists; they call us antichrists, and say that we went out from them; we say the like of them. But now this epistle has marked out the antichrists by this cognizance: "Whosoever denies that Jesus is the Christ," that same "is an antichrist." Now therefore let us enquire who denies; and let us mark not the tongue, but the deeds.