Genesis 4:13-14 OSB
Then Cain said to the Lord, “My guilt is too great to be forgiven! Surely You have driven me out this day from the face of the ground; I shall be hidden from Your face; I shall be groaning and trembling on the earth. Then it will happen if anyone finds me, he will kill me.”
Cain is worried about how he is affected by his action. He's more concerned with his fate than the murder of his brother or his offense against God. The focus on self is evident, but God responds with mercy. This mercy is lost on Cain as he departs from the presence of God, enters and joins the fallen world. There he will continue in his own way.