Marcan priority in the context of Two-source theory

The Gospel of Mark is the second of the four canonical Gospels and one of the three synoptic Gospels. It tells of the ministry of Jesus from his baptism by John the Baptist to his death, the burial of his body, and the discovery of his empty tomb. It portrays Jesus as a teacher, an exorcist, a healer, and a miracle worker. Jesus refers to himself as the Son of Man and is called the Son of God, though he keeps his messianic nature secret; even his disciples fail to understand him. This is in keeping with the Christian interpretation of prophecy, which is believed to foretell the fate of the messiah as a suffering servant.

Traditionally attributed to Mark the Evangelist, the companion of the Apostle Peter, the gospel is anonymous, and scholarship is inconclusive on its authorship. It is dated to around 70 AD and was likely written in Rome for a gentile audience. Mark is classified as an ancient biography and was meant to strengthen the faith of its readers. Most scholars hold that Mark is the earliest gospel and was used by both Matthew and Luke. Mark has therefore often been seen as the most reliable gospel, though this has recently been challenged.

The gospels of Matthew, Mark, and Luke are referred to as the synoptic Gospels because they include many of the same stories, often in a similar sequence and in similar or sometimes identical wording. They stand in contrast to John, whose content is largely distinct. The term synoptic (Latin: synopticus; Greek: συνοπτικός, romanized: synoptikós) comes via Latin from the Greek σύνοψις, synopsis, i.e. "(a) seeing all together, synopsis". The modern sense of the word in English is of "giving an account of the events from the same point of view or under the same general aspect". It is in this sense that it is applied to the synoptic gospels.

This strong parallelism among the three gospels in content, arrangement, and specific language is widely attributed to literary interdependence, though the role of orality and memorization of sources has also been explored by scholars. The question of the precise nature of their literary relationship—the synoptic problem—has been a topic of debate for centuries and has been described as "the most fascinating literary enigma of all time". While no conclusive solution has been found yet, the longstanding majority view favors Marcan priority, in which both Matthew and Luke have made direct use of the Gospel of Mark as a source, and further holds that Matthew and Luke also drew from an additional hypothetical document, called Q, though alternative hypotheses that posit direct use of Matthew by Luke or vice versa without Q are increasing in popularity within scholarship.

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.