Many for instance see parts of Book Four as arising from his debates with Florinus the Roman priest and alleged 'Valentinian.' I, however, have always been more interested in a particular tract that is found in the middle of Book Two. It deals with a heretical group we will identify with the Valentinian tradition for argument's sake (although the specific sect is not named in the piece) and their understanding of the 'year of favor' concept from Isaiah 61:2. It is a rather strange argument that unfolds here in Irenaeus because the Church Father does not seem to have originally known about Luke's reference to this important concept.
Irenaeus's argument is somewhat famous also for its peculiar notion that Jesus was 'almost fifty' when he was crucified. The claim develops against what is apparently the opinion that the heretics shared with Clement of Alexandria - namely that Jesus was almost thirty at the beginning of a ministry that lasted for a single year. The synoptic gospels cannot be naturally read in any other way other than suggesting all the events during Jesus's ministry fit within one calendar year. The gospel of John by contrast cannot be read in any other way than suggesting that Jesus's ministry happened over many years.
This is what makes Irenaeus's argument in Book Two so perplexing. The Valentinians are accused of 'making copious use of that according to John to illustrate their conjunctions' (cf. Adv Haer 3.11.7). The structure of Irenaeus's discussion in this section seems to 'assign' the Gospel of John to the Valentinians in the same way that Luke is given to the Marcionites. But it is important to note that the testimony of Irenaeus is far slipperier than that. In an earlier part of the same section, as Harnack notes, it would seem that the Marcionites also 'knew' of John (Adv Haer 3.11.2). The various statements that Irenaeus makes about the four gospels and their association with the heresies doesn't quite mesh the way scholars would like them to.
For instance if we go back to our first example, it isn't just that Irenaeus doesn't say that the Valentinians only use John to bolster their talk about aeons, but rather that they take things here and there from John but that he goes on to say that they:
shall be proved to be totally in error by means of this very Gospel, as I have shown in the first book.
The immediately difficulty that rarely gets recognized here is that Irenaeus did not simply write Book One and then Book Two and then Book Three and so on. We can be certain that he wrote a number of 'lectures' and then at some later date these works were incorporated into the Five Books in the manner of some literary headcheese - either by Irenaeus or more likely than not a later associate posthumously.
In other words, the person writing about the Valentinian use of the Gospel of John to bolster their claims about heavenly aeons 'already in Book One' was written at the latest stage in the development of the Irenaean material. At one time there were only a series of texts in which the Valentinian use of John developed. In due course Irenaeus's writings were assembled in a five volume work of which Book Three - and its reference to the Marcionite alleged use of Luke and the Valentinian use of John - can 'look back' at arguments which now lie in Book One. However when Irenaeus originally wrote these things there was no five volume work.
The reference in Book Two which has always fascinated me seems to have been written at a very early period, a time when there was no Gospel of Luke. Let us start by saying that Book Two itself is usually identified by scholars as being written around 177 CE. Book Three by contrast is usually identified during the Commodian period (180 - 192 CE). What always got under my skin I think is the fact that Irenaeus, while attacking the Valentinian understanding of a single year ministry for Jesus by means of the Gospel of John, he originally tackled their understanding of 'the favorable year' by means of Isaiah 61:2 rather than Luke 4:16 - 21.
The key distinction here is that Luke does not make reference to the 'day of recompense' that is found in Isaiah 61. Instead we read:
He went to Nazareth, where he had been brought up, and on the Sabbath day he went into the synagogue, as was his custom. He stood up to read, and the scroll of the prophet Isaiah was handed to him. Unrolling it, he found the place where it is written: “The Spirit of the Lord is on me, because he has anointed me to proclaim good news to the poor. He has sent me to proclaim freedom for the prisoners and recovery of sight for the blind, to set the oppressed free, to proclaim the year of the Lord’s favor.” Then he rolled up the scroll, gave it back to the attendant and sat down. The eyes of everyone in the synagogue were fastened on him. He began by saying to them, “Today this scripture is fulfilled in your hearing.”
Already in our preliminary discussion of this important passage in Irenaeus we see that we are wading into 'what Christians knew about the four gospels and when they knew it.'
Did the Valentinians have a copy of Luke and a copy of John - one which made reference to the 'year of favor' and the other to the details which Irenaeus claims they 'forgot' about a multi-year ministry of Jesus? Or did both Irenaeus and the Valentinians at one time share a single long gospel - i.e. a so-called 'Diatessaron' - which was attributed to John which contained elements now assigned in Irenaeus's later revisionary system to Matthew, Mark, Luke and John? The reason we ask this is because Irenaeus's original allusion to the heretical interpretation of the 'thirty years' and the 'year of favor' concept seem to share similarities with a gospel citation in Stromata Book One from the writings of Clement of Alexandria.
If I am correct, the original dynamic of Christianity in the second century was actually dominated by single, long gospels - what we might call 'Diatessarons' for argument sake. Irenaeus came from this milieu and used a text associated with 'John' which contained elements from the synoptic and what is now known as the 'Johannine' gospel tradition. At some point during his career - i.e. the material found in Book Three quite specifically - Irenaeus developed four false gospel types out of what we must imagine were four different Diatessaronic gospels which were in circulation during the late second century.
Already Epiphanius tells us that the Gospel according to the Hebrews - the text Irenaeus himself identifies with Matthew - was 'the Diatessaron.' The next text introduced in order in Adv Haer 3.11.7 is Luke which was originally associated with the Marcionite Diatessaron (cf. Adv Haer 3.11.2 and various identifications of Johannine material being used by the Marcionites in the writings of the Church Fathers no less than Matthew and Mark). Strangely, Mark is introduced after Luke, but with a kind of related sect (they are 'other' Marcionites apparently). We learn that our shorter Mark was developed from a longer Mark from Clement of Alexandria who seems very familiar with Tatian and presumably his rival Diatessaron (the Alexandrian Diatessaron is specifically associated with Ammonius Sacca). The existence of a Diatessaronic John would help explain why canonical John doesn't mention now the Transfiguration and other narratives which John was apparently a witness according to the synoptic tradition.
I have always likened this shortening of the four principle early (lost) Diatessaronic witnesses (i.e. Hebrews, Marcion, Ammonius Sacca and Tatian) to the development of the Mishnah which occurred around the same time in the Jewish communities. The Mishnah is a collection of legal interpretations from the various schools which were deemed acceptable. Even heretics were included in this catalog (although their names were obviously changed i.e. 'Elisha ben Abuyah' and R Meir aka Mayesha). I see the shortened gospel fabrication as essentially doing the same thing in terms of acceptable readings from the gospel. I don't believe that Irenaeus stayed faithful to the particular group associated with Matthew, Mark, Luke or John (i.e. Lukan readings are not 'Marcionite' even though the text was developed against Marcion).
Nevertheless we should be so naive to suppose that all the opinions of the school of Elisha ben Abuyah were not similarly transferred and attached to other groups in the very same manner.
