Genesis 3:15 I will put enmity between you and the woman, and between your offspring and hers; he will crush your head, and you will strike his heel.
This is God’s solution to the problem of sin, which he spoke to the devil. It is a messianic prophecy that is remarkable for at least three reasons.
First, Adam and Eve were not required to solve the problem. We might expect the first couple to pay for their own sin, but God promised to send another who would crush [the devil’s] head. This idea is developed throughout the Old Testament to help God’s people anticipate the Promised One.
Second, the Promised One would be male. He will crush your head, not She will crush your head. In a single pronoun God eliminated half the human race from the pool of possible candidates. And throughout the Old Testament the pool shrinks even further.
The Promised One would be descended from Abraham (Genesis 12:1-3), from the tribe of Judah (Genesis 49:10), born in Bethlehem (Micah 5:2), and minister in Galilee (Isaiah 9:1-2). If you put all the prophecies together, there is only one person who fulfilled them all perfectly. These are the very Scriptures that testify about me (John 5:39), said Jesus.
Third, the conflict between the serpent and the Promised One would likely include fatalities. If you step on a serpent’s head it will probably die. And if it bites your heel, you could also die. The crucifixion of Jesus Christ was fatal because he actually died. But through his resurrection, he dealt a fatal blow to Satan, that will bring him to his end. The life, death and resurrection of Jesus Christ was a cosmic conflict that saves us from our sins. It is also the main point of the Bible.