Two-source hypothesis

The two-source hypothesis (or 2SH) is an explanation for the synoptic problem, the pattern of similarities and differences between the three Gospels of Matthew, Mark, and Luke. It posits that the Gospel of Matthew and the Gospel of Luke were based on the Gospel of Mark and a hypothetical sayings collection from the Christian oral tradition called Q.

The two-source hypothesis emerged in the 19th century. B. H. Streeter definitively stated the case in 1924, adding that two other sources, referred to as M and L, lie behind the material in Matthew and Luke respectively. The strengths of the hypothesis are its explanatory power regarding the shared and non-shared material in the three gospels; its weaknesses lie in the exceptions to those patterns, and in the hypothetical nature of its proposed collection of Jesus-sayings. Later scholars have advanced numerous elaborations and variations on the basic hypothesis, and even completely alternative hypotheses that are increasing in popularity. Nevertheless, "the 2SH commands the support of most biblical critics from all continents and denominations."

When Streeter's two additional sources, M and L, are taken into account, this hypothesis is sometimes referred to as the four-document hypothesis.

The two-source hypothesis was first articulated in 1838 by Christian Hermann Weisse, but it did not gain wide acceptance among German critics until Heinrich Julius Holtzmann endorsed it in 1863. Prior to Holtzmann, most Catholic scholars held to the Augustinian hypothesis (Matthew → Mark → Luke) and Protestant biblical critics favored the Griesbach hypothesis (Matthew → Luke → Mark). The Two-Source Hypothesis crossed the channel into England in the 1880s primarily due to the efforts of William Sanday, culminating in B. H. Streeter's definitive statement of the case in 1924. Streeter further argued that additional sources, referred to as M and L, lie behind the material in Matthew and Luke respectively.

The hypothesis is a solution to what is known as the synoptic problem: the question of how best to account for the differences and similarities between the three synoptic gospels, Matthew, Mark and Luke. The answer to this problem has implications for the order in which the three were composed, and the sources on which their authors drew.

Any solution to the synoptic problem needs to account for two features:

The 2SH attempts to solve the synoptic problem by advancing two propositions, Marcan priority to explain the triple tradition, and the existence of a lost Q document to solve the double tradition. In summary, the two-source hypothesis proposes that Matthew and Luke used Mark for its narrative material as well as for the basic structural outline of chronology of Jesus' life; and that Matthew and Luke use a second source, Q (from German Quelle, "source"), not extant, for the sayings (logia) found in both of them but not in Mark.

The 2SH explains the features of the triple tradition by proposing that both Matthew and Luke used Mark as a source. Mark appears more 'primitive': his diction and grammar are less literary than Matthew and Luke, his language is more prone to redundancy and obscurity, his Christology is less supernatural, and he makes more frequent use of Aramaic. The more sophisticated versions of Mark's pericopes in Matthew and Luke must be either the result of those two "cleaning up" Mark, if his is the first gospel, or of Mark "dumbing down" Matthew and/or Luke, if he was later. Critics regard the first explanation as the more likely. On a more specific level, Marcan priority seems to be indicated due to instances where Matthew and Luke apparently omit explanatory material from Mark, where Matthew adds his own theological emphases to Mark's stories, and in the uneven distribution of Mark's stylistic features in Matthew.