The concept of the covenant is highly important for understanding Scripture. It is the key to interpreting and appreciating the Scriptures. When we understand the covenants and what their purpose, design and functions are then it helps us understand what is happening in the big picture of the bible. Covenants are often compared to marriage. However, this is one type of covenant that is not the type of covenant upon which all of Scripture is built. In Redemptive History there are three major covenants (Covenant of Redemption, Covenant of Works, and the Covenant of Grace). These covenants are not all alike. If marriage is a covenant, which I think it is, it is a parity covenant. A covenant of two equal parties coming together. This is not the type of covenant Adam was in nor is it the type of covenant Abram entered into.
We can see how those who translated the septuagint (LXX) understood covenant as they translated the hebrew into greek. They translated the hebrew word berit to the greek word diatheke. Diatheke is a type of covenant that is put in place when a sovereign imposes the covenant on another party. It is not a covenant of equals (this would have been the greek word syntheke). Robert Letham, in his book The Work of Christ, rightly states that those who were translating the Old Testament understood covenants made by God with humans to be one-sided. There are no equal parties with God when he makes a covenant. Letham writes:
These treaties were imposed on defeated vassal nations. They were not pacts between equals. Rather, they contained promises of benefits the suzerain was to grant and listed the obligations to which the vassal was bound. (40)
The Reformation held the covenant as a central interpretive theme for understanding Scripture. It was used for understanding our views of baptism, original sin, justification, election and assurance. This is why when our baptist brothers speak about baptism without reference to the covenantal grid, they are speaking right past us. When a non-Calvinist argues against Calvinism ignoring the covenantal grid, they are not reaching us. The covenantal structure for the Reformed churches is the central structure, skeleton, edifice upon which all our theology is built.
At the heart of the covenant is a promise, “I will be your God, you shall be my people”. This is usually followed by a covenant meal (Exodus 24) a ratification of the covenant. This is also why would take it weekly, if the Sunday service is a covenant renewal ceremony. The covenant therefore is intimate and relational. In this case, the intimacy and friendship of a marriage covenant would reflect that aspect of the biblical covenants. In the covenant, according to Murray, it is a “sovereign administration of grace and of promise”. But for Meredith Kline it was an administration where law has priority. (Letham, 40) Kline makes this distinction based on the nature of God. God is just by nature. God to be gracious however is based on something, that is it is dependent on his will.
This leads us to the great discussion Paul has of the law and promise in Galatians. (Gal 3:17-22) Here the covenant is certainly seen as a a gracious covenant of grace to man. We must see the covenant not coming on equal parties but as a sovereign giving this covenant to rebels. This does not mean the law is set aside. The law is regulative of the covenant. It has a function within the covenant. While grace can be seen as the basis of the covenant to begin with. The law is not destroyed in Jesus, it is fulfilled.