Those critical of a perspective that grants Israel a national reformation returning to its Davidic glory days might suggest that in fact the Church is Israel, founded on the work of Christ. But even if we concede that the Church and Israel have become interchangeable proper nouns, our research so far from the first few chapters of Luke leaves open the questions of how the term came to be re-understood, when this was done, and why. Whoever Luke’s original audience was, or even if we propose the Holy Spirit moved him to consider the saints of centuries to come, we must either be content to allow Luke’s gospel narrative to begin right where the OT story left off, or we force the conclusions of the future upon it. Either Luke intentionally begins his story from the perspective of Old Testament Israel, or his opening chapters are about the New Testament Church with absolutely no explanations and plenty of vaguely appropriate OT echoes which can be loosely applied to both the Church and Israel.
Since Luke chapter 1 includes no clear clues to redirect our thoughts, I take his narrative to begin exactly where the years of silence post-exile Israel left off. And this runs congruent with the reality that Jesus came to Israel. For instance, he came to announce salvation, a message which only makes sense when it starts with Israel and is extended to the whole world as in Isaiah 49:6. He came to announce the in-breaking of the Kingdom of God, a Kingdom that starts with Israel, and overcomes the whole world as in Daniel 7-12. The messages of the parables, undoubtedly, must start with Israel, before the universal individual messages can be reaped. The parable of the “lost sheep” for instance, makes the most sense in the context of passages like Jeremiah 50:6. All this is because Israel has always been integral, not secondary, to Gods soteriological purposes for the cosmos. Therefore, we must track Israel in the drama of Luke-Acts and allow the (I would say obvious) initial distinction between Israel and the Church to germinate without any outside influence.
The clear “us” (Jews) vs. them (gentiles) clash in Acts, I believe, comes from the post resurrection questions of “what happens now?” Acts is the only thorough treatment in the NT on the question of Israel’s future, and should be studied in a way that allows the reader to be equally be surprised at its conclusion as at the associated gospel’s.
To review points made thus far:
At the opening of Luke, the term “Israel” refers to the nation composed of 12 tribes that are mentioned in Exodus (Exodus 1:1-5). Whether the term Israel comes to include Gentiles later in Luke’s Gospel has not been discussed.
Israel contains within it two groups which we have named “believing” or “true” Israel, and “unbelieving” or “rebellious” Israel.
While southern Israel (Judah and Benjamin) had returned from Babylon, northern Israel remained scattered from the land. All the Major Prophets promised a return from exile as specifically a return for all 12 tribes, which YHWH would unite reunite from a righteous remnant. The throne of David, the eternal symbol of the once glorious undivided monarchy, is the prophetic key to this reunion. Jesus himself had all 12 tribes in mind as in Luke 22:30 (additionally mentioned in Matthew 19:28).
YHWH had established a specific covenant with Israel, which Zechariah invoked in his prophecy in Luke 1, because he expected God to act on behalf of Israel in order to end the exile and reinstate a righteous King.
The forgiveness of sins occurs in the context of the political and religious crimes of Israel.