When Adam and Eve broke the covenant of works, creation was thrown into upheaval. Pain and futility were introduced into the created order such that now men and women face great sorrow and hardship as they seek to fulfill the creational mandates of work and child-rearing (Gen. 3:16–19). Moreover, human nature was radically corrupted. From our youth, our bent is not toward fellowship with the Lord as it was before the fall but away from Him into disobedience (8:21).
The introduction of sin means that without God’s intervention, we cannot obey our Creator as He commanded. It also means that without the Lord’s actions, we will not even want to obey our Maker. Thankfully, God did intervene so that the death He promised Adam for eating the forbidden fruit would not be eternal for those whom He loves (see 2:15–17). Furthermore, He engaged in a covenantal intervention, as we see in today’s passage.
Genesis 3:15 gives us what is traditionally known as the protoevangelion, the “first gospel.” It is the first revelation of the covenant of grace. Under the covenant of works, a works principle was instituted whereby the blessings of the covenant would come about through the efforts of human beings—by obeying God perfectly, we could gain eternal life. However, under the covenant of grace, blessings are obtained by a grace principle that says someone else inherits the blessing of eternal life, and we share in it not through our good works but through faith alone. God’s grace to His people under the covenant of grace will produce obedience in them, but our obedience does not merit eternal life for us (see Rom. 4; James 2:14–26).
Sin and Satan conspire against human beings to keep us in bondage to wickedness and not in a right relationship with the Lord. Thus, the first revelation of the covenant of grace promises the final defeat of our enemies. In Genesis 3:15, God graciously ordains a war between the offspring of the woman and the offspring of Satan. The word “offspring” is a collective singular, meaning that it can refer both to a plurality and to an individual. Christ is ultimately the seed of the woman, and we see grace in that it is He, not us, who does the work necessary to defeat the devil. He bruises the serpent’s head, striking the fatal blow in the war. In Christ, we become the seed of the woman who share in His victory. God crushes Satan under our feet because Christ vanquished him on the cross (Rom. 16:20a).