The term “Progressive Revelation” is often used very casually, and can mean different things to different people. There is an important distinction in Jewish thought between what is new and what is illuminated at a later time. In Christian theology, revelation is often used of information that is “brand new” and revealed by God only to certain individuals. According to Jewish thought, whereas “revelation” is obviously a valid phenomenon, it often involves acquiring a deeper understanding of something already revealed. That is, sometimes a “full” (or complete) understanding of “something” is not revealed until the right time, or until the occurrence of a specific event.
For example, Paul (in his letter to the Romans) describes the “connection” that Jews and Gentiles have in the Messiah, not as a new revelation in the 1st-century, but as a “mystery hidden for long ages past (and) … now revealed (Rom 16:25-26). According to Paul, the coming of Yeshua makes it possible for a Gentile (a “wild olive shoot”) to be “grafted in” among the Jewish (the “natural olive) shoot(s)” of the “olive tree” (Rom 11:17-24). Further, “so that (the Gentiles) may not be conceited: Israel has experienced a hardening in part until the fullness of the Gentiles has come in. And so all Israel will be saved, as it is written: "The deliverer will come from Zion; he will turn godlessness away from Jacob. And this is my covenant with them when I take away their sins" (Rom 11:25-27).
Therefore, “progressive revelation” never involves God setting aside “Plan A” for “Plan B” because “things” didn’t work out as expected. Now, God does unfold His plans a little at a time, but “new” revelation is always connected to “previous” revelation.