Surah 8. Al-Anfal, Ayah 68

This 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.

 The decree that ransoming captives will be allowed.

Though any motive of worldly gain, which may have been in the minds of some among the victorious Muslim army, is condemned as worthy of a severe penalty, what actually happened is ascribed to the Plan of Allah, which was preordained. Among the prisoners taken were the Prophet's uncle 'Abbas and Hadhrat 'Ali's brother, Aqil, who afterwards became Muslims. 'Abbas was an ancestor of the founder of the celebrated 'Abbasi Dynasty which played such a notable part in Islamic history. In his case the promise made in verse 70 was amply fulfilled. In the case of all prisoners, if there was any good in their hearts, their very fight against Islam and their capture led to their being blessed with Islam. Thus does Allah's Plan work in a marvellous way, and evolve good out of seeming evil.