After Cain kills his brother, the Lord sets a curse upon him. I read the curse as Cain becoming “a fugitive and vagabond” (v36). Becoming a fugitive is “greater than [Cain] can bear” (v38). Which got me thinking, what exactly is a fugitive, and what is so bad about it? A fugitive is one who runs from the law. A fugitive is running, but can only run so far. His negative outcome is inevitable. Justice is never far behind.
It is interesting to note that although Cain is cursed, he still has what we often believe brings the most happiness, a family. He goes to the land of Nod (v41), and had many sons and daughters. His son even built a city (v42). Minus the cursing, this almost reads like a happily ever after story.