Chapter 3 covers the story of Cain and Abel, the sons of Adam and Eve. In short, Cain was jealous and angry at Abel because Abel seemed to be preferred by God. Cain murdered his brother. God punished Cain by making him roam the lands without a permanent home. In order to prevent him from being murdered because of his deeds and roaming, God said that anyone who murdered Cain would suffer vengeance seven times over.
Ancient Interpretation: Ancient interpreters decided the meaning of this passage was that some people will stop at nothing – not even murder. But God will punish those who are wicked. Thus there is a moral order to the universe.
In addition, they decided that Cain was not human, but that he was half demon. Although most modern translations of the Bible say that Eve bore Cain “with the help of the LORD,” the word “help” is not included in the original text. What the Bible literally says is “I have gotten a man with the LORD.” Of course, that does not mean that the LORD God was the father of Cain, as angels were also referred to as LORD. The conclusion ancient interpreters reached is that an evil angel had impregnated Eve, and that Cain was the offspring.
Modern Interpretation: Again, the modern interpretation that Kugel mentions is the etiological one. In this interpretation, the individual Cain actually symbolized an entire group of people called the Kenites, who were fierce warriors and who were nomads. Thus, when one Kenite was killed, they would retaliate by killing “seven” Israelites.