Two-source hypothesis in the context of Explanatory power

The Gospel of Luke is the third of the New Testament's four canonical Gospels. It tells of the origins, birth, ministry, death, resurrection, and ascension of Jesus. Together with the Acts of the Apostles, it makes up a two-volume work which scholars call Luke–Acts, accounting for 27.5% of the New Testament.

The text is anonymous, not naming its author. Perhaps most scholars think that he was a companion of Paul, but others cite differences between him and the Pauline epistles. In the popular Two-source hypothesis, Luke used the Gospel of Mark and a hypothetical collection called Q, with unique material often called L, though alternative hypotheses that posit the direct use of Matthew by Luke or vice versa without Q are increasing in popularity within scholarship. Luke follows Mark closely compared to other ancient historians’ usage of sources, though the parallels and variations of the Synoptic gospels are typical of ancient historical biographies. Luke tends to follow his sources closely when checked. The most common dating for its composition is around AD 80–90. The earliest witnesses for the Gospel of Luke are the Alexandrian and the revised western text-type.

The Q source (also called The Sayings Gospel, Q Gospel, Q document(s), or Q; from German: Quelle, meaning "source") is a hypothesized written collection of primarily Jesus' sayings (λόγια, logia). Q is part of the common material found in the Gospels of Matthew and Luke but not in the Gospel of Mark. According to this hypothesis, this material was drawn from the early Church's oral gospel traditions.

Along with Marcan priority, Q had been hypothesized by 1900, and remains one of the foundations of most modern gospel scholarship. B. H. Streeter formulated a widely accepted view of Q: that it was written in Koine Greek; that most of its contents appear in Matthew, in Luke, or in both; and that Luke better preserves the text's original order than does Matthew. In the two-source hypothesis, the three-source hypothesis and the Q+/Papias hypothesis, Matthew and Luke both used Mark and Q as sources. Some scholars have postulated that Q is actually a plurality of sources, some written and some oral. Others have attempted to determine the stages in which Q was composed.

The three-source hypothesis is a candidate solution to the synoptic problem. It combines aspects of the two-source hypothesis and the Farrer hypothesis. It states that the Gospel of Matthew and the Gospel of Luke used the Gospel of Mark and a sayings collection as primary sources, but that the Gospel of Luke also used the Gospel of Matthew as a subsidiary source. The hypothesis is named after the three documents it posits as sources, namely the sayings collection, the Gospel of Mark, and the Gospel of Matthew.

The sayings collection may be identified with Q, or with a subset of Q if some (typically narrative-related) material normally assigned to Q is instead attributed to Matthew's creativity in conjunction with Luke's use of Matthew.

The Q+/Papias hypothesis (Q+/PapH), advanced by Dennis R. MacDonald, offers an alternative solution to the synoptic problem. MacDonald prefers to call this expanded version of Q Logoi of Jesus, which is supposed to have been its original title.

The Q+/PapH has similarities to previous solutions to the synoptic problem. Like the two-source hypothesis, the Q+/PapH affirms that both Matthew and Luke have used a Q document. Like the Farrer hypothesis, it affirms that Matthew used Mark and that Luke used both Mark and Matthew. Like the modified two-document hypothesis, it affirms that Mark also used the Q document.

The four-document hypothesis or four-source hypothesis is an explanation for the relationship between the three Gospels of Matthew, Mark, and Luke. It posits that there were at least four sources to the Gospel of Matthew and the Gospel of Luke: the Gospel of Mark and three lost sources (Q, M, and L). It was proposed by B. H. Streeter in 1925, who refined the two-source hypothesis into a four-source hypothesis.