From Genesis chapter 4, we hear the story of Cain and Abel, Adam and Eve's children. When they grew up, they give offerings to God.  God respected Abel and his offering, but God didn't respect Cain's. Cain got so angry, he let sin get control of him. He killed his brother.  God had to punish Cain. Cain had to leave his home and go away from the Presence of God.