Thomas L. Thompson says the authors of the Gospels of Matthew, Luke, and Thomas used ancient, written wisdom literature to craft Jesus figure.
Thomas L. Thompson, The Messiah Myth: The Near Eastern Roots of Jesus and David (New York: Basic Books, 2009), 133
It is already clear that the examination has falsified the thesis of the Jesus Seminar. The teaching of Jesus cannot be reconstructed from the hypothetical Q source for Matthew and Luke's gospel and the fourth-century Gospel of Thomas. The sayings we have looked at are not atypical of the sayings Jesus is given to speak in the gospels. They belong not to oral tradition, but to a large and important cluster of ancient wisdom sayings and have been used by both the gospel writers and the Jesus Seminar to create their figures of Jesus.