Gospel of Thomas in the late 2nd century that "since there are four quarters of the earth ... it is fitting that the church should have four pillars ... the four Gospels" ("Against Heresies", 3.11.8), and then shortly thereafter made the first known quotation from a fourth gospel—the canonical version of the Gospel of John. The late 2nd-century Muratorian fragment also recognizes only the three synoptic gospels and John. Bible scholar Bruce Metzger wrote regarding the formation of the New Testament canon, "Although the fringes of the emerging canon remained unsettled for generations, a high degree of unanimity concerning the greater part of
Gospel of Peter in the canonical gospels was transmitted orally, through readings in the churches, i.e. that the text is based on what the author "remembers" about the other gospels, together with his own embellishments. Ron Cameron and others have further speculated the Gospel of Peter was written independently of the synoptic gospels using an early proto-gospel. A consequence of this is the potential existence of a source text that formed the basis of the passion narratives in Matthew, Luke, and Mark, as well as in Peter. Origen makes mention of the Gospel of Peter as agreeing with the tradition of the Hebrews.