We need not restrict the case to esoteric truths about Jesus. Aileen Guilding (The Fourth Gospel and Jewish Worship [Oxford: Clarendon Press, 1960]) has argued that the discourse of John 6:35–50 draws on texts that would have been familiar from the Jewish lectionaries of the time.
Behind this discourse, then, may lie a homily expounding such texts. Must we assume that such a “homily” found in the gospel was a later Christian composition? No, claims Raymond E. Brown (The Gospel According to John, [New York: Doubleday, 1966], vol. 1, pp. 278–280). Why should it not have been a homily of Jesus himself?
In 1985 John A.T. Robinson (The Priority of John, [London: SCM, 1985]) explored the possibility of giving John “procedural” priority over the other gospels: Instead of fitting John into the Synoptic framework, he proposed to fit the Synoptic Gospels into John’s. The result, he claimed, was utterly compelling.