In order to account for this common material, scholars have conjectured a document they call Q (from the German word Quelle, source). This hypothetical document is used to explain the many sayings of Jesus that appear in Matthew and Luke, but not in Mark. In this theory, both Matthew and Luke used two documents, hence the name “two source theory.” Some scholars assume that this document must have existed in one form or another. For example, G. N. Stanton says that “we can be reasonably certain that Q existed as a written document” (650). Yet scholars such as Thomas Edgar vehemently deny its existence. Edgar states that “Q has never been seen nor is there any evidence that such a document ever existed” (147). The recent book Gospel Writing by Francis Watson makes a compelling case for some sort of Sayings Source, but he does not particularly like the implication of a multi-layered Q document sometimes described int he literature.
There is something about the idea of a source document which makes evangelicals uneasy. We do not want to accept the idea that Matthew and Luke were scholars and editors, assembling their gospels from sources. Most conservatives would dismiss Q immediately because it is the product of Historical Criticism (as the essays in The Jesus Crisis do). Did God inspire Matthew and Luke to edit their sources, or write their gospels? For the conservative scholar, Q simply is not helpful since their emphasis is on the text as it appears in the Bible.
This unease is felt over a broad spectrum of scholarship as well. The essays in Questioning Q, for example, wonder if relying on the existence of a Sayings source has short-circuited the idea of the Gospel writers as creative writers who should be treated as authors, not editors of their books.
Both of these warnings are well intended. It is true that documents which “count” are the synoptic Gospels as they appear on the page of the Bible. If the writers used sources, that may not matter much for our interpretation of the words in Matthew, Mark and Luke. I have always tried to get students to “stay within the world of the story” and read Matthew as Matthew, not as a parallel book to Luke.
Yet the evidence is there, and as I read it Matthew used Mark and a sayings source of some kind. Luke likely also used Mark and a sayings source, although he could have also used Matthew. For me, it is not correct to mis-characterize Matthew as cut and pasting sources together to create his gospel. Rather, if Matthew used courses, he was a scholar marshaling all of his resources to create a theological document which answered some questions about the person and nature of Jesus and the idea of discipleship after the resurrection. There is nothing wrong with the idea that Matthew (or Mark) used sources, but too much emphasis on the sources will obscure the goal – a clear reading of the Gospels.
Bibliography: Thomas Edgar. “Source Criticism: The Two Source Theory,” pages 132-157 in The Jesus Crisis (ed. Robert Thomas and F. David Farnell; Grand Rapids: Kregel, 1998); Mark Goodacre, editor. Questioning Q: A Multidimensional Critique (Downers Grove: Inter-Varsity, 2004); G. Stanton. “Q”, pages 644-650 in The Dictionary of Jesus and the Gospels (ed. Joel B. Green and Scot McKnight; Downers Grove: Inter-Varsity, 1992).