It has become increasingly common for skeptics to say that there is no real difference of quality between the canonical gospels -- the ones in the New Testament -- and the non-canonical gospels. The claim is increasingly made that equally viable gospels were "suppressed" by political means as an exercise in the winners writing the history books.
When I first decided to see whether there was anything to this, I set out to read the non-canonical gospels. I was forcefully struck by an impression that these were very different in general quality from the New Testament gospels. But I wanted to be sure, and I asked myself, "Is it simply a matter of my familiarity with the canonical gospels, or is there something objectively, measurably different about the non-canonical gospels?" I set about seeing if there was a way to actually measure differences in a way that anybody could fact-check for themselves.
In this post, I'll cover one of the first things I noticed: the non-canonical gospels, by and large, have a Jesus who is not particularly Jewish, and disciples who are not particularly Jewish. I've done a more thorough write-up previously; for now I want to mention that I'm hardly the only one to have noticed this.
As a case in point, I'd like to introduce a book to you that demonstrates this fairly well. It's a Jewish book on the history of the liturgy. My regular readers will know I'm very fond of liturgical prayer. In my research on the history of the liturgy, I came across a book described by its dust jacket as "the most complete scholarly study of Jewish liturgy in existence today." Naturally, I couldn't resist getting a copy. The book is Jewish Liturgy: A Comprehensive History by Ismar Elbogen. The original edition (1913) was in German. At the time of the 1993 English translation, it was noted (again, from the dust jacket), "Eighty years after its first appearance, Elbogen's magisterial work remains the most thorough academic study of the Jewish liturgy ever written." His primary sources are many and varied, including the Talmud, Josephus, Philo of Alexandria, a host of Jewish writers through the ages, Matthew, Mark, Luke, John, Acts, Paul's letter to the Galatians, the Didache, Justin Martyr, and the Apostolic Constitutions, among others. Curiously (or not so curiously), I have not been able to find any references in this book to the Gospel of Mary, or the Gospel of Philip, or any of the non-canonical gospels.
Before we look at why this might happen, I should mention why this work takes so much notice of certain Christian writings: it uses them to establish historical facts about Jewish liturgy and worship, especially as it is practiced in the synagogue. The canonical gospels contain first-century evidence of what Jewish worship was like. There is a record of Hanukkah being celebrated in Jerusalem under the name the Feast of Dedication; it is applicable to the discussion of the history of Hanukkah. The book considers parallels between traditional Jewish prayers and other prayers recorded in the canonical gospels, and uses that to show how far traditional Jewish prayers were already developed at that point in time. The canonical gospels were referenced for peoples' reactions to the practice of giving scholars preferred seats in the synagogues, for whether the Jewish synagogue worship already included readings from the prophets and sermons on those readings, for whether the twice-weekly fast was already in place before the fall of the Temple. There is evidence on the development of the role of the synagogue leader in speaking to people who were out of order; when Jesus heals on the Sabbath, the fellow who objects has the proper title for the person who was supposed to maintain order in the synagogue. There is even evidence in the New Testament for some very detailed aspects of the Jewish liturgy: that the person who gave the sermon was first called to read, that the reading occurred while standing, that the sermon occurred while sitting. The gospels are used as evidence for the location of certain particular synagogues, and for the practice (also known elsewhere) that non-Jews might contribute to building a synagogue. All these very Jewish facts in the New Testament are placed alongside a continuum of Jewish writings to form a coherent whole of which they are an integral piece. Here I have focused only on the gospels, but the book takes the same approach to the book of Acts and Paul's letter to the Galatians.
So this author's interest in the New Testament comes down to this: how much historical information can you learn about first-century Jewish worship in general, and in particular the liturgical worship common in synagogues? The Jesus in the canonical gospels is a regular at the synagogue.
As for the non-canonical gospels, I have looked through the Gospel of Mary, the Gospel of Philip, the Gospel of the Savior, the Gospel of Thomas, the Gospel of Truth, the Infancy Gospel of Thomas, and the Protoevangelium of James; I have found on-line electronic editions of these to double-check my searches. I have not found a reference to a "synagogue" in any of them. Exactly how Jewish is a Jesus who never goes to a synagogue?
If the historical Jesus is a Jewish figure of interest in the area of religion, that's a huge point, that some gospels (Matthew, Mark, Luke, and John) can be used by historians of Jewish liturgy and provide useful data on first-century Jewish worship, while other gospels do not even mention a synagogue, much less provide detailed information on first-century Jewish worship practices. That is a measurable difference in the quality of the works. The works that are measurably better in telling us about first-century Jewish religious life just happen to be the ones that the early Christian church found to be better sources in general. Large numbers of non-canonical gospels have a Jesus who never goes to a synagogue; the works are of no historical interest for scholars of first-century Judaism. Their Jesus seems ... out of context for a first-century Jew. If we grant that the historical Jesus is Jewish, then here is one objectively measurable point in favor of the canonical gospels having more to say about the historical Jesus.