Michael D. Coogan, The Old Testament: A Literary and Historical Introduction to the Hebrew Scriptures, third edition (OUP, 2014), 118.
The concept of covenant is central to the Bible. Its significance is indicated by its thematic importance in P, which is organized around three covenants, those between God and Noah, God and Abraham, and God and Israel. On a broader level, the two principal divisions of the Bible in Christianity are called the Old Covenant (“Testament”) and the New Covenant. As the word “testament” suggests, a covenant is a legal term.
The Hebrew word for covenant, berit, has an uncertain etymology, perhaps meaning a bond or mutual agreement. In the Bible, berit means something like “contract,” and it is used for legal agreements such as marriage (Ezek 16.8; Mal 2.14; Prov 2.17), debt-slavery (Job 41.4; compare Deut 15.17), solemn friendship (1 Sam 18.1-4), and especially treaties. On several occasions in the Bible, we are told of treaties between rulers. These are of two types: a parity treaty, in which the two parties are equals, and a suzerainty treaty, in which one party, the suzerain, is superior to the other, the vassal, to use medieval terms.