God gave Cain a clear choice and a warning: sin is not unbeatable, but it must be actively resisted. This verse is the heart of the chapter — a call to self-control and right living.
Memory phrase: Say no to sin at the door.
Talk about it: If sin is like a hungry animal waiting at the door, what can you do to keep the door shut?
Prayer: God, help me choose what is right even when it is hard. Help me say no to the bad things that want to come in.