Q? - I Am Not Wholly Convinced.

If Mark was written first, this explains the similarities that Mark has to Matthew and Luke. Nevertheless, there are many striking similarities between Matthew and Luke, which have no corresponding passage in Mark (the so-called "double tradition"). Most of these passages are comprised of Jesus' teachings. Therefore, many New Testament specialists think that there may have been a document in the early Church that no longer exists that was a collection of Jesus' teachings. This source is usually designated as "Q" (from the German quelle, "source"). This Q document would have been used by Matthew and Luke to enhance their Gospels with material about Jesus' teachings above and beyond Mark. Q would then explain the close similarities between Matthew and Luke that are not in Mark. No manuscript evidence exists for Q. Some New Testament scholars even think Q was not a written document but just an oral collection of sayings that was repeated as a group. If Q did exist as a document, it probably would have fallen out of use simply because its material would already be found in Matthew and Luke. A similar fate almost befell the Gospel of Mark. Early Christians greatly neglected Mark simply because they preferred to read Matthew which they thought contained Mark plus a whole lot more!