Cain was the first son of Adam and Eve. A farmer by trade, he brought some of the fruits of the ground to God while his brother Abel brought an animal sacrifice. Genesis 4 tells us that God was pleased with Abel's offering, but not Cain's. The Hebrew construction emphasizes that Abel went out of his way to please God, while Cain is described as merely discharging a duty. Angry that his sacrifice was not accepted by God, Cain murdered his brother. In addition, Cain denied the act and gave no evidence of repentance. God cursed Cain, assigning him to be a "restless wanderer," but also placed a mark on him, protecting him from vengeance. What that "mark" constituted has been the subject of wide speculation, without much consensus.
