68لَولا كِتابٌ مِنَ اللَّهِ سَبَقَ لَمَسَّكُم فيما أَخَذتُم عَذابٌ عَظيمٌMuhammad AsadHad it not been for a decree from God that had already gone forth, there would indeed have befallen you a tremendous chastisement on account of all [the captives] that you took.1This is apparently a reference to the captives taken by the Muslims at Badr, and the discussions among the Prophet's followers as to what should be done with them. 'Umar ibn al-Khattab was of the opinion that they should be killed in revenge for their past misdeeds, and in particular for their persecution of the Muslims before the latters' exodus to Medina; Abu Bakr, on the other hand, pleaded for forgiveness and a release of the prisoners against ransom, supporting his plea with the argument that such an act of mercy might induce some of them to realize the truth of Islam. The Prophet adopted the course of action advocated by Abu Bakr, and released the captives. (The relevant Traditions are quoted by most of the commentators, and especially - with full indication of the sources - by Tabari and Ibn Kathir.) The reference in the above verse to the "tremendous chastisement" that might have befallen the Muslims "but for a decree (kitab) from God that had already gone forth" - i.e., a course of action fore-ordained in God's knowledge makes it clear that the killing of the captives would have been an awesome sin.