I think it helps looking at a broad context. The Gospel of Matthew wasn’t written as a part of a compilation – it was intended by St. Matthew to be a stand-alone book.
Who was Matthew’s audience? Who was he writing to?
The Jews.
What do the Jews care about?
The Scriptures, Moses & King David & Abraham, and authority. They care about authority in particular because of the power struggles going on at the time (see: Pharisees and Sadducees, oppression by tyrants, captivity, exile, etc.), and indeed the question of authority present throughout the entirety of the OT. Matthew would have to address this in some way.
Does Matthew address these things?
Yup.
Scripture: He quotes from the OT more than 100 times. Matthew takes pains to assuage the fears of the Jews that the Old Law would be abolished and their faith for nothing (Matt 5:17 et seq), but then clarifies some misconceptions (ibid).
Patriarchs: He trace’s Christ’s geneology back to David and Abraham, and does a wonderful job of
paralleling Moses and Christ.
Authority: As a Protestant I’d be a little stuck. I could try to (mis)use Matt 15 and 23 to condemn tradition, but even if this were so it still wouldn’t tell me what the authority is (and it would
really upset the Jews - not exactly Matthew’s intent given the audience). I could try to use the various passages of Christ saying “it is written”, but there are plenty of instances where He did not.
As a Protestant trying to look through Jewish lenses, I can’t find a single place where Our Lord told us who our *earthly *authority would be. Obviously, our eternal authority is Christ - but how will we know with any certainty what Christ meant in the ambiguous phrases? If there’s a dispute on doctrine, there’s no answer given by Matthew to the Jews on how to settle it…reading through Protestant lenses. And this should be rather disturbing, given that the Jews
really, really cared about this. One would not expect St. Matthew to let such an important topic to the Jews be completely neglected in a letter to the Jews.
As a Catholic, I can point to Matt 16 and 18. As a Jew I would then look at Matt 16 in light of Isaiah 22 and Matt 18 in light of Deu 17:8-13. The passages parallel, and the answer is pretty clear what’s going on. Further, Matt 10 is pretty explicit about how Christ feels about the Apostles. Finally, the final paragraph of Matthew is rather explicit on who is to be the
earthly voice of Christ – i.e., if you have a doctrinal problem, you know to whom to turn to get it answered. If you know your OT (as the 1st Century Jews would), and you know the structure of the OT kingdoms (again, as the 1st Century Jews would), the solution to the question of authority is fairly evident.
So the question isn’t why would Isaiah 22 have any connection to Matt 16, but rather why
wouldn’t it?!?
God Bless,
RyanL