It is not uncommon to read studies that either state explicitly or work under the assumption that the synoptic problem has been solved. Using the parables of the Mustard Seed and the Leaven as a test-case, it becomes clear that the problem is far from a solution. Each of the three major source hypotheses has its strengths (and weaknesses) when it attempts to account for the data generated by these two peri copae. Although this paper concludes that the Two-Document Hypothesis (2DH) deals with the data with the fewest problems, the strengths of the other hypotheses coupled with the weaknesses of the 2DH should help keep the 2DH honest.
Journal for the Study of the New Testament
College of the Humanities

Crook, Z.A. (2000). The Synoptic Parables of the Mustard Seed and the Leaven: A Test-Case for the Two-Document, Two-Gospel, and Farrer-Goulder Hypotheses. Journal for the Study of the New Testament, 22(78), 23–48. doi:10.1177/0142064X0002207802