Tafsiran Kejadian 3:15: Rashi, Chizkuni, Ramban & Sforno

ואיבה אשית AND I WILL SET ENMITY — Your sole intention was that Adam should die by eating it first and that you should then take Eve for yourself (Genesis Rabbah 20:5), and you came to speak to Eve first only because women are easily influenced and know how to influence their husbands; therefore “I shall put enmity [between thee and the woman]”.

ואיבה אשית, “and I will set enmity, etc.” Rashi’s comment, printed in our chumashim as belonging to this verse, although appearing at the end of G-d’s speaking to the serpent, refers to the original intention of the serpent to cause Adam’s death as a result from eating of the fruit of the tree of knowledge; the reason it had not tried to seduce Adam, G-d was well aware of, was that it is easier to deceive women, so that the woman was used as the serpent’s tool in seducing Adam. The Torah adds this line in order to show how much the punishment fitted the crime, the ultimate objective of the serpent having been (according to Rashi’s source (Bereshit Rabbah, 20,5 ) that it would marry the woman.

AND THOU SHALT BRUISE THEIR HEEL. This means man will have an advantage over you [the serpent] in the enmity between him and you for he will bruise your head but you will bruise him only in his heel, with which he will crush your brain.