Among the non-canonical (apocryphal) Gospels are three that are usually grouped together and called “Jewish-Christian Gospels.” These are very tricky texts to deal with. We don’t have any manuscripts of them – even small fragments. They come to us, instead, in isolated quotations of church fathers such as Origen, Didymus the Blind, Jerome, and Epiphanius. These (orthodox) church fathers sometimes quoted or referred to one or the other of the Gospels in order to relate what it said; and sometimes it was in order to attack what it said. There are all sorts of questions raised about the no-longer-surviving Gospels in these quotations.
A good part of the problem is that some of these fathers – especially Jerome, on whom we depend for most of our information for two of the three Gospels – quite obviously confused things, or were confused themselves in what they had to say, since what they have to say about these Gospels doesn’t add up and in the end doesn’t make sense. On this every scholar who works on these things agrees.
The fathers virtually all believed or assumed that the various Jewish-Christian Gospels were in fact only one Gospel not three (some scholars think there were only two), that it was called something like “the Gospel According to the Hebrews,” that it had been written originally in Aramaic (or Hebrew), and that it was in fact an altered version of the canonical Gospel of Matthew, in use among a sect of Jewish Christians (i.e., those who thought that one should keep the Jewish law as well as believe in Jesus as the Messiah). Much of that simply can’t be true – especially that