This famous verse--often cited as the first proclamation of the gospel--gave a silver lining of mercy to the curse that followed it. In Genesis 1:28, God made childbearing a blessing. But in Genesis 3:16, He frustrated our enjoyment of it. Did God's blessings end here? No.
First, consider the context for the promise of Genesis 3:15. Prior to Chapter 3, God placed Adam and Eve in a location (Eden) literally meaning "delight" (2:8)--He put them in a paradise! At the end of Chapter 3, God banished them from the paradise (3:23). In between these two events, Satan (in the form of a serpent) deceived Adam and Eve and ruled over them (Genesis 3:1-7). What is the significance of God's promise of a future crushing blow to the serpent (today's verse)? In this context, God's promise foretold of a return to the pre-serpent, pre-Chapter 3 state, implying a return to paradise and the full blessing of God.
Second, consider the specific fulfillment of the promise of Genesis 3:15--Christ Himself. His life, death, and resurrection defeated the serpent's rule and paved a way for us to enjoy blessings that will take an eternity to exhaust.
The irony in all this? God promised a return to paradise by means of childbearing ("her seed")--the vehicle of the curse.
Though Adam likely did not know the specific fulfillment of Genesis 3:15, he seems to have believed the promise of restoration through childbearing ("seed"). He named his wife Eve ("life") "because she was the mother of all living" (Genesis 3:20). For those who believe through Christ, a return to Paradise (Luke 23:43) awaits. NTJ