(But recite unto them) O Muhammad (with truth) with the Qur'an (the tale of the two sons of Adam, how they offered each a sacrifice, and it was accepted from the one) Abel (of them and it was not accepted from the other) Cain. ((The one)) Cain (said) to Abel: (I will surely kill thee) O Abel. ((The other) answered) why? Because Allah has accepted your offering and rejected mine. And Abel said: (Allah accepteth only from those who ward off (evil)) the sincere in their speech and action, whose hearts are pure, and your heart is not pure.