How did Cain respond to God's rejection of his offering?

Cain's response to God's rejection was one of anger and dejection. In Genesis 4:6-7, God questioned Cain about his anger, offering him the opportunity for forgiveness if he did well. However, Cain's pride and refusal to recognize his need for a proper sacrifice led him to act out in rage. He ultimately killed his brother Abel, an innocent victim, out of jealousy and resentment toward God's acceptance of Abel's offering. This act not only marked the first murder but underscored the deep-rooted animosity that often arises when human works are contrasted with divine acceptance based on grace. Cain's failure to repent ultimately sealed his fate in his sin.