The inimitable Fred Sanders examines the opening lines of the four Gospels :
Say youre an apostle or one of their disciples, and your job is to write a gospel. What are the rules for how you start a gospel? Well, there are only four real gospels, lets check them out real quick.
Mark begins this way: The beginning of the gospel of Jesus Christ. Well, thats easy, very straightforward. Oh, it goes on, The beginning of the gospel of Jesus Christ, the son of God, as it was written in Isaiah the prophet, Behold I send my messenger . . . prepare the way of the Lord. With some prophecy. Nice. It gets you back into the kings of Israel, back before the Babylonian captivity. So God didnt just think up this gospel thing, hes been talking about it since Isaiah. And then John the Baptist says I baptized you with water, but He will baptize you with the Holy Spirit. So when Jesus shows up, we know what to expect. Nice work, Mark.
Now Matthew does all of that, too, but he has a different plan for an introduction. He wants to go even further back, to make sure youve got enough context, so he says, the book of the genealogy of Jesus Christ, the Son of David, the Son of Abraham. See that, hes reaching further back than Isaiah, going back through David to Abraham. Nice work, Matthew. Way to start a gospel.
Luke comes in like a reporter, and says, Inasmuch as many have undertaken to compile a narrative of the things that have been accomplished among us . . . it seemed good to me also . . . to write an orderly account for you, most excellent Theophilus, that you may have certainty concerning the things you have been taught. And then he provides all kinds of backstory, two whole chapters about the events leading up to the birth of Jesus, and even a story about something Jesus did when he was twelve. Finally he gets to a genealogy, and decides to trace that family tree back through David and Abraham to Adam.
See what he did there? Its almost like the gospel writers are in a contest to see who can start the good news of Jesus far back enough to get the whole picture in; a contest to see who can get you to open your mind wide enough to get the whole context to make sense of the Jesus story. Mark starts with Isaiah, Matthew with Abraham, Luke starts with Adam. Adam! Beat that! You cant get older than Adam.
Well, here comes John, and he beats it. John is not messing around. His opening move: IN THE BEGINNING. Thats older than Adam, isnt it? Its almost like hes saying Thats the trump card, no more gospels. Four is quite enough, and besides, theres really nowhere to go from here, now. What are you going to do, say before the beginning? Copycat.
Its like when kids are fighting back and forth with a times two, oh yeah, times four, oh yeah, and then one of them the Infinity Card. Oh yeah, times INFINITY. Once the infinity card is exposed, the game is kind of over.