The story of Adam and Eve’s children Cain and Abel doesn’t take up much room in the Bible. The story of their lives takes up one chapter, with a few genealogical deals added in the next one. Despite this, the phrase “Cain and Abel” is known throughout our culture, and we all have a fairly good idea of what it means. Let’s take a closer look at what the Bible actually says about these two men and their lesser-known siblings.
Who Were Cain and Abel?
As adults, Cain and Abel took separate careers: Abel became a shepherd while Cain became a farmer (Genesis 4:2). At some point, Cain and Abel both gave offerings to God from their produce. Cain gave crops from his harvest, while Abel gave sections of firstborn lambs. God accepted Abel’s offering but did not approve of what Cain brought. Cain was upset and jealous of Abel as a result (Genesis 4:5), and God warned Cain to be careful:
“Why are you so angry?” the Lord asked Cain. “Why do you look so dejected? You will be accepted if you do what is right, then watch out! Sin is crouching at the door, eager to control you. But you must subdue it and be its master.”
Later (the date is not clear, just “one day”) Cain asked Abel to walk with him in the field, and Cain killed Abel. God took a tactic similar to the one he used in Genesis 3:9 after Cain’s parents had eaten the forbidden fruit: He approached the wrongdoer and asked a question. In this case, he asked Cain, “Where is your brother?” Cain responded, “I don’t know… am I my brother’s guardian?” (Genesis 4:9).
God rebuked Cain for his actions and told him that from this point he would be “a homeless wanderer on the earth” (Genesis 4:12). Cain replied that he could not bear the punishment of forever wandering and that “anyone who finds me will kill me!” God replied that he would punish anyone who killed Cain seven times over, and put a mark on Cain so that anyone who tried to kill Cain would be warned off (Genesis 4:15-16). After this point, Cain had a son named Enoch and founded a city, and had various descendants who developed skills like playing music, forging metal, and nomadic herding (Genesis 4:17-24).
Why Did Cain Kill Abel?
God approved of Abel’s offering but not Cain’s, and as a result, Cain resented his brother. Why precisely God didn’t approve of Cain’s offering is hard to say. It’s worth noting that the Bible says Cain gave “some of his crops,” without describing the quality of the offering (Genesis 4:3). In contrast, the next verse says that Abel gave “the best portions of the firstborn lambs from his flock.” Abel gave the best, and he took it from the first results of his labors, not as an afterthought or after he was sure he had a surplus.
We don’t get any such details about Cain’s crops, which may mean he didn’t give the best. Cain may simply have not been showing proper respect toward God with his offering. Regardless of what Cain did wrong, the fact that God told Cain he would be accepted if he did what was right (Genesis 4:7) indicates there was generally something wrong with his offering.
Not only was Cain jealous of God favoring Abel, but he also didn’t appreciate the warning that God gave him. He was warned, and yet he continued to behave rebelliously. Even after he killed Abel, his rebellious attitude continued, as seen in his scoffing response, “Am I my brother’s guardian?” (Genesis 4:9).
In essence, Cain’s response was self-centered. The result was that he became a wanderer, a man with no community. He lived for himself and got only himself in return.
Who Was Seth?
Genesis 4:25-26 picks up after the story of Cain’s family and says that Adam and Eve had another son named Seth. After Seth was born, Eve said, “God has granted me another son in place of Abel, whom Cain killed” (Genesis 4:25). Seth later had a son named Enosh (Genesis 4:26), and genealogy in Genesis 5 focuses on Seth’s descendants, ending with Noah who would become famous for building the ark.
At first glance, Genesis 4-5 sounds like it’s saying Adam and Eve didn’t have any children between Abel and Seth. It says that “After the birth of Seth, Adam lived another 800 years and he had other sons and daughters,” (5:4) as if there was a long period where it was just Adam, Eve, and their two sons followed by a big expansion after Seth. However, this misses a couple of things.
First, Cain said after God cursed him that he feared, ‘anyone who finds me will kill me!” If there were no other children of Adam and Eve around at this point, who could Cain be talking about? Some scholars have suggested the answer is that Adam and Eve were not the first and only human beings created, simply the ones Genesis focuses on because they are the ones who lived in the Garden of Eden. However, after Adam and Eve sinned in Genesis 3, God said, “Look, the human beings have become like us,” talking about them as representatives of their entire species. 1 Corinthians 15 continues this method by describing Adam as the first human. It says “For as in Adam all die, so in Christ, all will be made alive” (15:22) and that “The first man was of the dust of the earth; the second man is of heaven” (15:47). Therefore, it seems that Adam and Eve were the first human beings.
Second, Genesis 5 talks about Adam’s lineage without mentioning Cain and Abel at all. It starts by saying “this is a written account of the descendants of Adam,” then says, “When Adam was 130 years old, he became the father of a son who was just like him… He named his son Seth” (5:3). This genealogy doesn’t record every single descendant of Adam, only select ones. Therefore, Adam Eve could have had more children between Abel and Seth, and likely did. We just don’t know how many, whether Cain and Abel grew up with many brothers or sisters.
Did Adam and Eve’s Sons Marry Their Sisters?
Assuming that Adam and Eve were the first man and woman, and there no “Pre-Adamic” beings that humans mated with, it would seem that Cain and Seth Eve must have married women descended from Adam and Eve.
As established, we don’t know when Adam and Eve started having daughters (or for that matter whether Abel had a wife and children unmentioned in the narrative). We also know that Adam was 130 years old when Seth was born, so there could have been several generations of people born in between Genesis 4:1 and Genesis 4:17 (the first time that Cain’s wife is mentioned). Therefore, we don’t know whether Cain or Seth married their direct siblings—one of them might have done so and the other married a niece or cousin. Regardless, sheer math would indicate that at least one of Adam’s three sons married a sister.
This idea is disturbing and goes against the laws forbidding incest in Leviticus 18. However, prior to this law being given in Leviticus, there are various instances of men marrying their sisters or other relatives. Abraham’s wife Sarah was his half-sister by a different mother (Genesis 20:11-13). Jacob married two of his female cousins (Genesis 29-30). Moses’ father married his aunt (Exodus 6:20). For whatever reason, the law against incest doesn’t seem to have been in effect (at least not as strictly) before God made the covenant with the Israelites at Mount Sinai.
Why this shift occurred is hard to say. Since Genesis describes all that was created in the Garden of Eden as good, including Adam and Eve, their genes may have been well-developed to the point that their kids could marry siblings and produce children with no genetic defects. This would fit the shift we see in Genesis from early generations with long lives producing children past their 100s to humans with shorter lives and shorter fertility rates. We go from Adam and Eve, who were still having children when they were over 100 years old (Seth was born when Adam was 130), to Abraham and Sarah who were past child-bearing age when Sarah was 90 and Abraham 100 years old (Genesis 17:17, 18:12). In Genesis 6:3, God decrees that humans will only live to be 120 years old, and other than a few patriarchs this holds true throughout the rest of the Bible.
So, it’s possible that in Cain and Abel’s period, human genetics were so good that all the biological problems that incest creates (mutations, etc.) weren’t a problem. Regardless, God does forbid incest later (and then quite firmly) in the Bible. However we interpret who Adam and Eve’s sons married, we are left with the fact that the Bible doesn’t tell us every single bit of information we want. It gives us the facts we need and leaves us with reminders that whatever strange things people in the Bible did, God knew what he was doing and worked something good from it down the line.