Genesis 4.  Cain’s offering had disappointed God.  The reason was that God looked not at the offering, but at the heart of the offerer.  God warned Cain that he had a choice.  He could rule over his sinful heart, or he could allow it to overcome him.  He chose sin and death.  He murdered his brother.

God had been watching.  He banished Cain, forcing him to abandon the ground, because the ground would abandon him.  He would be a fugitive and wanderer on the earth, and he and his descendants would not be known for their farming skills.  His descendants would also inherit his lack of self-control.  Seven generations later, the lust for vengeance is still active in his family, as is demonstrated by Lamech’s poem.

LORD, heal our hearts.  Sin seeks to consume us, as it did Cain.  Most of us do not murder, but all of us have murder in our hearts, like a crouching beast waiting to pounce (7).  Grant us the fruit of your Holy Spirit – which is self-control.