The chapter
The first crime on the new earth was not theft or idolatry. It was a brother killing a brother over acceptance.
The two sons of Adam each offered a sacrifice. It was accepted from one and not the other: "Allah only accepts from the God-conscious." Qabil's answer to rejection was not to correct his own heart but to remove the one whose offering was accepted: "I will surely kill you." Habil's reply is one of the most quietly devastating sentences in the Qur'an: "If you stretch out your hand against me to kill me, I will not stretch out my hand against you to kill you, I fear Allah, Lord of the worlds." He was not weak; he was restrained. He preferred meeting Allah wronged over meeting Him as a wrongdoer.
Qabil killed him and became of the losers, and then did not even know what to do with the body. Allah sent a raven scratching the ground to show him how to hide the corpse of his brother. The first burial in human history was taught by a bird, and the first murderer's reaction was not triumph but regret: "Woe to me, am I unable to be like this raven?"
Directly from this story the Qur'an legislates for all time: "Whoever kills a soul, unless for a soul or for corruption in the land, it is as if he had slain mankind entirely; and whoever saves one, it is as if he had saved mankind entirely." And the Prophet ﷺ tied every unjust killing until the Day of Judgment back to this moment: "No soul is killed unjustly but a share of its blood falls upon the first son of Adam, for he was the first to establish killing."
Envy, the disease of Iblis, who could not bear Adam's honor, became the disease of Adam's own son. The Path will meet it again and again: the brothers of Yusuf, the chiefs of Quraysh, every generation that hated the one whom Allah preferred.