There is none. Reseach the "Q" source. It's amazing! The synoptic gospels are a JOKE. Scholars theorize that Mark was written first while Luke and Matthew were written much later and are obvious works of plagiarism. "Q" may have been a common list of Jesus quotes. The areas where Mark, Matthew and Luke deviate from each other give evidence that each author cherry picked quotes from another unknown source called "Q."
Also, google "New Testament Plagiarism from Hebrew Scriptures" and prepare to be blown away. Of course, as JWs and ex-JWs, we may be familiar with most of these similarities because it was pounded into our heads that any similarity is "PROOF of the Bible's accurate prophecies!" Bah Humbug! The New Testament is nothing more than a pastiche of old Jewish writings and tweaked enough to start a new religion DECADES after Christ was allegedly living. Moses and Jesus have so many similarities it's astonishing: (A ruling king orders the execution of all babies in the land at news of their arrival. Moses and Jesus both impressed religious leaders with their intelligence as children, both fasted alone for 40 days, both made many identical quotes--some verbatim--about freeing "my people.") Isaac and Jesus do as well (They were both products of miraculous births. Their dad's both offered them up for sacrifice. Isaac had to gather the wood for the altar, Jesus had to carry his "toture stake," Abraham's altar was built on the same mountain later identified as the Mt. of Olives). King David and Jesus: (David's sidekick drew a sword against Absalom's sidekick and David told him to put it away just like Jesus said to Peter when he drew his sword---BOTH ACCOUNTS occured in the Garden of Gethsemane!) Sure, you can say "Hey! Proof of prophecy!" Or, you can apply Occam's Razor and ask what's more likely? And why would the almighty creator of the universe confine himself within the perameters of a literary device like forshadowing? "Oh, well, you see, this account pictures that... you know... just because. Why? Because! Jehovah made it that way..."
BULLCRAP. Only FICTIONAL NOVELS do that!
Another glaring example even appears in the NWT. At Mark 13:14, the author--obviously copying from another pamphlet--mistakenly includes instructions that are so out of place it will blow your mind. Surely, Jesus wouldn't have said, "let the reader use discernment" as a parenthetical aside during his speech about the last days LOL! That's like an actor saying "exit stage right" or "turn page" in the middle of a play! Ridiculous.