The Bible is, ultimately, one Book. Like a good book, we must read the beginning to understand the middle and end. This truth applies to individual chapters as well. To understand Genesis 4:26, we must understand what precedes it.
Genesis 3:15 states, "And 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." Thus, Satan will have offspring ("thy seed"), Eve will have offspring ("her seed"), and Satan will seek to harm her offspring: "thou shalt bruise his heel." But Eve's seed will ultimately prevail: "it shall bruise thy head"--a bruise to the head would be a crushing blow. Based on these verses, we should expect to find many accounts in Scripture describing attacks of Satan on the seed of the woman.
The first such attack arrived quickly. Adam and Eve had two children (Genesis 4:1-2): one was righteous (Abel--Matthew 23:35), the other was a child of Satan (Cain--1 John 3:10-15). Though death was promised as a punishment for sin (Genesis 2:17), the first death was not from natural causes; Cain murdered Abel (Genesis 4:8). Clearly, Satan was trying to destroy the righteous seed of the woman.
Did God's promise fail? This chapter's closing verses gave the answer: "She bare a son, and called his name Seth: For God, said she, hath appointed me another seed instead of Abel, whom Cain slew. And to Seth, to him also there was born a son . . . then began men to call upon the name of the LORD." Satan's plan was foiled; God granted righteous seed.
God's promises will never be thwarted. What a cause for rejoicing! NTJ