Revisiting Rendtorff's Covenant Formula

I may return to my series on Blum in the future. Right now, I want to write some on Rolf Rendtorff's Covenant Formula. I'm not entirely satisfied with my posts on that book, so I decided to read a couple of book reviews to see what the book's main argument was. Essentially, Rendtorff was looking at the formula of "You will be my people, and I will be your God" throughout the Hebrew Bible. He prefers a synchronic approach because that is more conducive to theological analysis, and he argues that biblical authors inserted the Covenant Formula at crucial stages in Israel's history to affirm God's commitment to Israel: Circumcision (Genesis 17, which is P), Sinai/Horeb (P, Deuteronomy), and the promise of a new covenant (Jeremiah 31). I don't think that this book contradicts other things that Rendtorff has written: that independent units were combined under the rubric of God's promises, and that someone united the patriarchal story with the Exodus story. Rendtorff's point appears to be that an editor inserted the Covenant Formula into the Tetrateuch for theological purposes.