And I will put enmity between thee and the woman, and between thy seed and her Seed; He shall bruise thy head, and thou shalt bruise His heel. -Genesis 3:15

These words were not directly spoken to Adam and Eve, but they were directed distinctly to the serpent himself, and that  was of punishment to him for what he had done. It was a day of cruel triumph to him such joy as his dark mind is capable of had filled him, for he had indulged his malice, and gratified his spite. He had in the worst sense destroyed a part of God’s works, he had introduce sin into the new world, he had stamped the human race with his own image, and gained new forces to promote rebellion and to multiply transgression, and therefore he felt that sort of gladness which a fiend can know who bears a hell within him. But now God comes in, takes up the quarrel personally, and causes him to be disgraced on the very battle-field upon which he had gained a temporary success. He tells the dragon that He will undertake to deal with him; this quarrel shall not be between the serpent and man, but between God and the serpent. God saith, in solemn words, “I will put enmity between thee and the woman, between thy seed and her Seed,” and He promised that there shall rise in fulness of time a champion, who, though He suffer, shall smite in a vital part the power of evil, and bruise the serpent’s head. This was the more, it seems to me, a comfortable message of mercy to Adam and Eve, because they would feel sure that the tempter would be punished, and as that punishment would involve blessing for them, the vengeance due to the serpent would be the guarantee of mercy to themselves. Perhaps, however, by thus obliquely giving the promise, the Lord meant to say, “Not for your sakes do I this, O fallen man and woman, nor for the sake of your descendants; but for My own name and honour’s sake, that it be not profaned and blasphemed amongst the fallen spirits. I undertake to repair the mischief which has been caused by the tempter, that My name and My glory may not be diminished among the immortal spirits who look down upon the scene.” …The divine sovereignty and glory afford us a stronger foundation of hope than merit, even if merit can be supposed to exist. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/1326.cfm