Genesis 4:9 - Matthew Poole's English Annotations on the Holy Bible

Where is Abel? Not that God was ignorant where he was, but partly to convince him of his sin, and to lead him to repentance, and partly to instruct judges to inquire into causes, and hear the accused speak for themselves, before they pass sentence. Thy brother, whom nature and near relation obliged thee to love and preserve. Am I my brother's keeper? Why dost thou inquire of me concerning him who is of age to look to himself? Is he such a stripling that he needs a guardian? Or didst thou ever make me his guardian?