Is Mark the Source for Matthew and Luke?

The most popular theory in contemporary Biblical study is the “two source hypothesis.” This theory proposes that the Gospel of Mark and a source of the sayings of Jesus (called “Q”) were the sources for the Gospels of Matthew and Luke. However, calling it a “two source” theory is an oversimplification since the Gospels of Matthew and Luke are also considered to have their own independent source which would give each of them three sources.

While this is currently the most widely accepted theory it is not without critics and debate.