If You Will Keep My Covenant

The way covenants function in the Scriptures is what I consider a problem area for interpretation and theologizing. I suppose it may have something to do with the noncovenantal thinking of the evangelicalism in which I've been reared. But I think it also has to do with the way the whole Bible hangs together, which is a very complex matter.

Exodus 19:5 is an example of this. Which covenant is in view? Here's what William Dumbrell says, which seems right-minded to me: 

The covenant in mind may be prospective and have Exodus 20 in view. In the OT, however, references to keeping a divine covenant are consistently to a covenant already in existence (Gen. 17:9-10; 1 Kgs. 11:11; Ps. 78:10; 103:18; 132:12; Ezek. 17:14). It is possible that Exodus 19:5 points back to 6:5 and 3:13-15 and that continuity with the patriarchal covenant is involved, especially in light of the patriarchal style of address with which Yahweh begins verse 3. Involved in the Sinai arrangement that follows is continuity within the Abrahamic covenant but, for Israel, a specialized responsibility within the covenant. 

 —The Faith of Israel: A Theological Survey of the Old Testament (Grand Rapids: Baker, 2002), 37.