"The traditional answer to this question -- that Mark's Gospel is our very earliest -- is no longer foolproof, if it ever was to begin with. If our assessment of the Gospels as historical documents occasioned by actual exigencies within early Christianity is anywhere near the mark, then it follows that, however much we value the internal evidence, it is totally overshadowed for the New Testament critic by the evidence of the early fathers."
Why Four Gospels? (p. 78).
