Jesus quotes from the Old Testament often. For example, "Man shall not live by bread alone, but by every word that proceedeth out of the mouth of God." (Deuteronomy 8:3 & Matthew 4:4) and "Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh." (Genesis 2:24 & Matthew 19:5)
Jesus is particularly fond of quoting from the Psalms. A few examples are "Out of the mouth of babes and sucklings" (Psalm 8:2 & Matthew 21:16), "My God, my God, why hast thou forsaken me?" (Psalm 22:1 & Matthew 27:46) and "The LORD said unto my Lord, Sit thou at my right hand, until I make thine enemies thy footstool." (Psalm 110:1 & Matthew 22:44)
In fact, it's been estimated that 10 percent of the New Testament is composed of quotes from the Old Testament. The entire Gospel of Mark appears to be based on the Old Testament with little or no original material. Which raises the question, if Jesus had actually existed as a historical figure, why does Mark have to rely on the Old Testament so heavily? Why doesn't Mark know anything about Jesus outside the scriptures?
The Gospels of Matthew and Luke are both largely based on Mark, showing their ignorance of a historical Jesus is just as profound. (The Gospel of John appears to be a gnostic document which was rewritten to cohere with the synoptics.) However, Matthew and Luke contain material not found in Mark. Could this material be derived from an actual historical Jesus? First, let's take a look at the context in which this material appears.
Compare Luke 22:30 and Matthew 19:28. Luke places the phrase "That ye may eat and drink at my table in my kingdom, and sit on thrones judging the twelve tribes of Israel" during the last supper, while Matthew places it during Jesus' passage into Judea.
"No servant can serve two masters: for either he will hate the one, and love the other; or else he will hold to the one, and despise the other. Ye cannot serve God and mammon." In Luke (16:13), Jesus says this to the Pharisees after telling them the parable of the unjust steward. In Matthew (6:24), this is part of the sermon on the mount.
"And I say unto you, Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you. For every one that asketh receiveth; and he that seeketh findeth; and to him that knocketh it shall be opened." In Luke (11:9-10), Jesus says this after telling his disciples the parable of the friend at midnight. In Matthew (7:7-8), it's part of the sermon on the mount.
Since Matthew and Luke almost always put these sayings in different contexts, it's obvious Matthew wasn't based on Luke or vice versa. (We can also point out the contradictions between them, for example both give completely different genealogies for Jesus.) While Matthew and Luke are both based on Mark, they are independent of each other. So, how did similar sayings not found in Mark find their way into Matthew and Luke?
Scholars theorize that the sayings came from a now lost document known as Q (from the German Quelle which means "source"). The similar sayings found in Matthew and Luke but not in Mark probably came from a written source since the wording between Matthew and Luke is almost exactly the same, even if the contexts are wildly different.
So if Matthew and Luke are basically two different ways of combining Mark and Q together, what exactly is the nature of Q? Q was likely a sayings document similar to the gnostic Gospel of Thomas. In fact, Q and the Gospel of Thomas have 37 sayings in common (known as the Common Sayings Tradition or CST).
I'll examine where the sayings of Q could have come from in my next post.