“I will put enmity between thee and the woman, and between thy seed and her seed; it shall bruise thy head and thou shalt bruise his heel.” Genesis 3:15. This enmity is not natural. When man transgressed the divine law, his nature became evil, in harmony with Satan. Fallen angels and wicked men united in desperate companionship. Had not God interposed, Satan and man would have entered into an alliance against Heaven, and the whole human family would have been united in opposition to God. GrH_c 5.1
When Satan heard that enmity should exist between himself and the woman, and between his seed and her seed, he knew that by some means man was to be enabled to resist his power. GrH_c 5.2