Genesis 4:10-12 NIV
The Lord said, “What have you done? Listen! Your brother’s blood cries out to me from the ground.  Now you are under a curse and driven from the ground, which opened its mouth to receive your brother’s blood from your hand.  When you work the ground, it will no longer yield its crops for you. You will be a restless wanderer on the earth. ”
Just as there were consequences for the serpent, Eve and Adam in Genesis 3, so there are here for Cain. What we do matters, every action impacts on our world and each other, for good or for ill. For Cain, his work and relationship with the soil was disrupted, and also perhaps his mental well-being – he becomes restless, lost perhaps to his regret and what he had thrown away.
Spirit, keep us alert to the consequences of our actions as a church and as individuals, that we might build up and not destroy.