The most recent episode of New Testament Review is a crossover with Mark Goodacre’s NT Pod and covers Percy Gardner Smith’s Saint John and the Synoptic Gospels. Readers of the canonical Gospels know that the fourth Gospel is an odd duck. Some have suggested that it was composed without any knowledge of the Synoptics and the presence of pericopes similar to that of the Synoptics is owing to oral tradition. But as Ian Mills, Laura Robinson, and Mark Goodacre explain, this is probably wrong. For one, oral tradition explains too much; its fluidity is quite the liability in terms of explanatory power. For another, the similarities between the Johannine Gospel and the Synoptics seems to betray John’s knowledge of them, even if he was willing to disagree with and depart from these earlier authors.
In John’s Gospel, we find two types of evidence of Johannine knowledge of Synoptic material: direct verbal parallels and knowledge of synoptic episodes. Examples of the former include John 5:8-9 and Mark 2:11-12, specifically where Jesus tells a healed man, “Stand up, take your mat…” (NRSV).
John 5:8 – Legei autō ho Iēsous, Egeire aron ton krabatton sou kai peripatei.
Mark 2:11 – Soi legō, egeire aron ton krabatton sou kai hypage eis ton oikon sou.
Examples of the latter include parallel episodes like the cleansing of the temple (John 2:12-22; Mark 11:15-19), the feeding of the five thousand (John 6:5-14; Mark 6:30-44) and others. L. Michael White, following Moody Smith’s work, writes,
The position taken here [i.e. in Scripting Jesus] is that the Gospel of John both knew and depended on one or more of the Synoptics (probably Mark and Luke, at least) as well as other early Gospel materials, but it radically reshaped the narrative for dramatic effect in light of new social and theological contexts.
That seems right to me, though I’ve honestly been holding on to John’s independence from the Synoptics for some time. But, much like my belief in the existence of Q, it has slowly been eroded and today I no longer believe John was ignorant of the Synoptics.
 See L. Michael White, Scripting Jesus: The Gospels in Rewrite (New York: HarperOne, 2010), 354, 355.
 White, Scripting Jesus, 353.