Unlike the covenant of works made with Adam and all his descendants, God unfolds the covenant of grace through several successive covenants. The Noahic covenant is the first of these, a pact wherein God promised to preserve the stability of nature as an arena in which to fulfill the covenant of grace (Gen. 8:20–22). Following the covenant with Noah and his posterity, the Lord called Abram the patriarch out of paganism and pledged to make from him a great nation (12:1–3).
Later, the Abrahamic covenant is further clarified when Abram complains to God that he must make his servant the heir of his estate since he has no natural-born children (15:1–3). The Lord responds with a promise to give Abram a son, and Abram, believing this promise, is justified in God’s sight (vv. 4–6).
Yet Abram’s faith soon begins to waver, just as we often have trouble believing God. Entertaining questions about the Creator’s ability to give Abram the land of Canaan, Abram asks the Lord for a sign that He will keep His promise (vv. 7–8).
Instead of rebuking Abram for his doubt, God tells Abram to kill and cut up some animals and to lay their pieces side by side in two lines in order to form a pathway between them (vv. 9–11). With this command, the Lord shows Abram a vital truth, using an ancient Near Eastern practice. During covenant-making ceremonies in Abram’s day, the parties to the agreement often slaughtered and then divided the animals, walking between the pieces to signify that they would meet the same fate if they broke their oaths. When Abram kills the animals, he probably expects God to walk with him between the carcasses to seal the covenant. This is not what happens, however, for only a smoking pot and flaming torch, a visible manifestation of the Lord Himself, pass between the animal parts (vv. 12–16). God alone takes upon Himself the covenant curse if He does not keep His promise to Abram.
God swears this oath before changing Abram’s name to Abraham and before instituting the sign of circumcision (chap. 17). The Lord is pledging to fulfill His promise no matter what His people do. Of course, our obedience is important. But God, knowing our sin will lead us to fail, reveals that He alone will be able to keep covenant. He must take the initiative and do the work to reckon us obedient to His standards.