For this reason also [John] has thus testified to us in his Epistle: "Little children, it is the last time; and as ye have heard that Antichrist doth come, now have many antichrists appeared; whereby we know that it is the last time. 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 departed], that they might be made manifest that they are not of us. Know ye therefore, that every lie is from without, and is not of the truth. Who is a liar, but he that denieth that Jesus is the Christ? This is Antichrist."
This is obviously a loose quotation of 1 John 2.18-22 (NASB):
18 Children, it is the last hour; and just as you heard that antichrist is coming, even now many antichrists have appeared; from this we know that it is the last hour. 19 They went out from us, but they were not really of us; for if they had been of us, they would have remained with us; but they went out, so that it would be shown that they all are not of us. 20 But you have an anointing from the Holy One, and you all know. 21 I have not written to you because you do not know the truth, but because you do know it, and because no lie is of the truth. 22 Who is the liar but the one who denies that Jesus is the Christ? This is the antichrist, the one who denies the Father and the Son.
In 3.16.6-7, Irenaeus goes on to quote several other canonical works (Habakkuk, Galatians, and others), none of them happening to be a Johannine epistle (though the gospel is cited at least once). He returns to an epistle of John in 3.16.8:
These are they against whom the Lord has cautioned us beforehand; and His disciple, in his Epistle already mentioned [praedicta epistola], commands us to avoid them, when he says: "For many deceivers are entered into the world, who confess not that Jesus Christ is come in the flesh. This is a deceiver and an antichrist. Take heed to them, that ye lose not what ye have wrought."
But this quote is not from the "aforementioned epistle" at all; it is from 2 John [1.]7-8 (NASB):
7 For many deceivers have gone out into the world, those who do not confess the coming of Jesus Christ in the flesh. Such a one is the deceiver and the antichrist. 8 Watch yourselves, so that you may not lose what we have worked for, but may win a full reward.
Irenaeus immediately continues:
And again does he say in the Epistle: "Many false prophets are gone out into the world. Hereby know ye the Spirit of God: Every spirit that confesseth that Jesus Christ is come in the flesh is of God; and every spirit which separates Jesus Christ is not of God, but is of antichrist."
So he is now back to quoting (and interpreting) 1 John again: 4.1-3 (NASB) to be exact:
1 Beloved, believe not every spirit, but try the spirits whether they are of God: because many false prophets are gone out into the world. 2 Hereby know ye the Spirit of God: Every spirit that confesseth that Jesus Christ is come in the flesh is of God: 3 And every spirit that confesseth not that Jesus Christ is come in the flesh is not of God: and this is that spirit of antichrist, whereof ye have heard that it should come; and even now already is it in the world.
And he continues, again immediately:
These words agree with what was said in the Gospel, that "the Word was made flesh, and dwelt among us." Wherefore he again exclaims in his Epistle, "Every one that believeth that Jesus is the Christ, has been born of God;" knowing Jesus Christ to be one and the same, to whom the gates of heaven were opened, because of His taking upon Him flesh: who shall also come in the same flesh in which He suffered, revealing the glory of the Father.
The gospel quote comes from John 1.14, but the quote from the epistle is from 1 John 5.1:
1 Whoever believes that Jesus is the Christ is born of God, and whoever loves the Father loves the child born of Him.
Now, obviously not every patristic quotation is aptly delivered, and Irenaeus may simply be confusing 1 and 2 John. It would probably not be a hard thing to do.
But there is also the Muratorian canon:
[41] The Epistle of Jude indeed and the two with the superscription "Of John" [superscriptio Iohannis duas] are accepted in the Catholic [Church].
Why are only two Johannine epistles considered canonical here? (For that matter... which two?) The Muratorian canon is full of barbaric spelling and other weirdness, so maybe it is just a silly mistake, or maybe the brute fact is that the author simply has only two Johannine epistles in mind, and either was ignorant of the other one or regarded it as spurious.
Or... maybe these two data (from Irenaeus and the Muratorian canon) go together. What if 1 and 2 John actually circulated in some way as one single epistle, while 3 John remained separate? One might think of how 2 Corinthians 8, 9, and 10-13 are often considered to have originally been separate Pauline letters which were all gathered up into one grand Corinthian correspondence along with 2 Corinthians 1-7, as if they all belonged to the same epistle. What if a particular recension of the Johannine epistles, known both to Irenaeus and to the author of the Muratorian fragment, tagged 2 John onto 1 John in a similar manner? Then, when eventually the recension known to us caught up to it, people realized that 2 John had originally been a separate letter, and they simply "uncombined" them in accordance with the recension of three separate letters.
Thoughts?
Ben.