(Genesis 3:15 NET)The Lord God said to the serpent, 'Because you have done this... I will put hostility between you and the woman and between your offspring and her offspring; her offspring will attack your head, and you will attack her offspring's heel.'
Thesis: Genesis 3:15 was not intended by its author as a prediction of Satan's ultimate defeat by Christ. Nor did early Christians understand it as such.
Early Christian interpretation
Early Christians probably did not see in Genesis 3:15 a reference to Christ for the following reasons.
1. They never directly quote the text. Potential allusions to it in Luke 10:19 and Romans 16:20 are better explained with reference to LXX Psalm 91:13 which reads: "Over the asp and basilisk you will tread (ἐπιβαίνω), and you will trample (καταπατέω) the lion and the serpent (δράκων)." Unlike Genesis 3:15, only this verse in Psalm 91 makes mention of stepping upon snakes—a feature common to Luke 10:19 and Romans 16:20. Further, the word "strike/attack" (שׁוּף) in the Hebrew text of Genesis 3:15 does not imply the use of the man's foot as both the man and the snake lash out (שׁוּף) at each other. One could just as easily envision here the man striking the snake with a stick (cf. Isaiah 14:29, 27:1). So since it lacks the implication of "treading upon" the snake in Genesis 3:15, we should prefer Psalm 91:13 as the subtext for Luke 10:19 and Romans 16:20.
2. The LXX, the primary source of the scriptures for the early Christians, makes no mention of striking in Genesis 3:15 at all. Instead, the translators have man and snake "watch out" (τηρέω) for each other. Jews who read the Septuagint therefore had little reason to see in Genesis 3:15 a reference to the serpent's eventual destruction. What was in mind was rather an unending war between humans and snakes—a clear reference to a natural reality.
Hebrew Context
The author of Genesis 3:14-19 had in mind a perpetual struggle between man and snake, not an ultimate defeat of the snake.
1. Genesis 3:15, like verses 14-19, represents a curse, not a prophecy. The man will labor to produce food from the ground; the woman will produce fruit from her womb in pain; man and wife will struggle against each other (cf. verse 16 in NET and ESV). Each of these curses introduces constant conflict into the lives of the characters. So like the man and the woman, man and snake will also struggle against each other. With eternal enmity, they will exchange blows forevermore. No glimmer of hope, whether for the snake's defeat or for an eventual truce, is offered.