On Midrash
 

Spong--expounding upon Goulder--gives a thorough examination in his book "Liberating the Gospels". Midrash was a tool perhaps used by the Evangelists. Here is a good example from Liberating The Gospels:

... They are written, to a greater or lesser degree, in the midrashic style of the Jewish sacred storyteller, a style that most of us do not begin even now to comprehend. This style is not concerned with historic accuracy. It is concerned with meaning and understanding. The Jewish writers of antiquity interpreted God’s presence to be with Joshua after the death of Moses by repeating the parting of the waters story (Josh. 3). At the Red Sea that was the sign that God was with Moses (Exod. 14). When Joshua was said to have parted the waters of the Jordan River, it was not recounted as a literal event of history; rather it was the midrashic attempt to relate Joshua to Moses and thus demonstrate the presence of God with his successor. The same pattern operated later when both Elijah (2 Kings 2:http://neonostalgia.com/forum/Smileys/default/cool.gif and Elisha (2 Kings 2:14) were said to have parted the waters of the Jordan River and to have walked across on dry land. When the story of Jesus’ baptism was told, the gospel writers asserted that Jesus parted not the Jordan River, but the heavens. This Moses theme was thus being struck yet again (Mark 1:9 ff.), and indeed, for a similar purpose. The heavens, according to the Jewish creation story, were nothing but the firmament that separated the waters above from the waters below (Gen. 1:6-8). To portray Jesus as splitting the heavenly waters was a Jewish way of suggesting that the holy God encountered in Jesus went even beyond the God presence that had been met in Moses, Joshua, Elijah, and Elisha. That is the way the midrashic principle worked. Stories about heroes of the Jewish past were heightened and retold again and again about heroes of the present moment, not because those same events actually occurred, but because the reality of God revealed in those moments was like the reality of God known in the past. As this journey through the Gospels progresses, we will watch this midrashic principle operating time after time."--Spong, p. 36-37