What, then, can help us in understanding the whole message of the Torah? Central to the unifying plan of God in the Torah (and the rest of the Bible) is the concept of the covenant with its content forming the promise-plan of God. The notion of covenant is one of the key concepts of the Old and New Testaments, for the Latin word testamentum was later used by the church father Origen to refer to the two covenants of the Bible: the old covenant between God and Israel (Ex. 19:5) and the new covenant of Jeremiah 31:31-34 that was mediated by Jesus to the church (Heb 8:1-13).
To understand what these ancient covenants signified, it is best to begin with the political treaties known as suzerainty treaties. A suzerainty treaty was a political agreement made by a king in the ancient Near East with a subordinate ruler or nation that pledged his or its allegiance to the greater king. Those treaties are best exhibited among the Late Hittite Empire from the years 1400-1200 B.C. A modified form of suzerainty treaties was found in the first century B.C. among the Assyrians. These suzerainty treaties deleted two or three of the classical elements found in the earlier Hittite form that is parallel to Deuteronomy. …
What is remarkable about this outline is that there was a most decisive difference between the second and first millennium treaty forms. Since Deuteronomy follows the Hittite form of the second millennium type, this has enormous implications for the dating of this portion of the Pentateuch and makes the whole documentary hypothesis both unnecessary and very much beside the point. As Meredith Kline, who was among the first to point out this implication, remarked:
Now that the form critical data compel the recognition of the antiquity not merely of this or that element within Deuteronomy but of the Deuteronomic treaty in its integrity. . . any persistent insistence on a final edition of the book around the seventh century B.C. can be nothing more than a vestigial hypothesis no longer performing a significant function in Old Testament criticism.
Thus the suzerainty treaties were the model for Yahweh’s covenant as written, not merely as transmitted orally, that was mediated through Moses to the nation of Israel. But this signifies that Israel thought of Yahweh not as a kind of impersonal ground of all being, but as One who could speak and One to whom they should listen.
-Walter Kaiser in The Old Testament Documents: Are They Reliable and Relevant?, p. 143-145.