Abdullah bin Abbas reported,

When the prisoners had been taken captive, the Messenger of Allah ﷺ said to Abu Bakr and Umar, "What do you think should be done with these captives?"Abu Bakr said, "Prophet of Allah, they are our cousins and kinsmen. I think you should accept a fidya from them, which will give us strength against the disbelievers. Perhaps Allah will guide them to Islam."The Messenger of Allah ﷺ then asked, "And what do you think, son of Khattab?"Umar said, I replied, "No, by Allah, Messenger of Allah, I do not share the view of Abu Bakr. I think you should hand them over to us so that we may strike off their necks. Hand Aqeel over to Ali so that he may strike off his neck, and hand over so-and-so to me," naming a relative of his own, "so that I may strike off his neck. These men are the leaders of disbelief and its champions."The Messenger of Allah ﷺ inclined toward what Abu Bakr had said and not toward what I had said. The next day I came and found the Messenger of Allah ﷺ and Abu Bakr sitting and weeping.I said, "Messenger of Allah, tell me what has made you and your companion weep. If I find cause to weep, I shall weep, and if I do not, I shall weep along with you both anyway."The Messenger of Allah ﷺ said, "I am weeping over what your companions proposed to me, that they take the ransom. Their punishment was shown to me, nearer than this tree," a tree close to the Prophet of Allah ﷺ.And Allah revealed, "It is not for a prophet to have captives until he has thoroughly subdued the land" [Anfal 8:67], down to His words, "So consume what you have taken of war booty, lawful and good" [Anfal 8:69]. Thus Allah made the spoils of war lawful for them.

عن ابن عباس قال

فلما أسروا الأساري قال رسول الله ﷺ لأبي بكر وعمر: ما ترون في هؤلاء الأسارى؟ فقال أبو بكر: يا نبي الله! هم بنو العم والعشيرة، أرى أن تأخذ منهم فدية فتكون لنا قوة على الكفار، فعسى الله أن يهديهم للإسلام، فقال رسول الله ﷺ: ما ترى يا ابن الخطاب؟ قلت: لا والله يا رسول الله! ما أرى الذي رأي أبو بكر، ولكني أرى أن تمكنا فنضرب أعناقهم، فتمكن عليا من عقيل فيضرب عنقه، وتمكني من فلان (نسيبا لعمر) فأضرب عنقه، فإن هؤلاء أئمة الكفر وصناديدها فهوى رسول الله ﷺ ما قال أبو بكر، ولم يهو ما قلت، فلما كان من الغد جئت فإذا رسول الله ﷺ وأبو بكر قاعدين يبكيان، قلت: يا رسول الله! أخبرني من أي شيء تبكي أنت وصاحبك، فإن وجدت بكاء بكيت وإن لم أجد تباكيت لبكائكما، فقال رسول الله ﷺ: أبكي للذي عرض علي أصحابك، من أخذهم الفداء، لقد عرض علي عذابهم أدنى من هذه الشجرة (شجرة قريبة من نبي الله ﷺ) وأنزل الله عز وجل: {ما كان لنبي أن يكون له أسرى حتى يثخن في الأرض} [الأنفال: ٦٧] إلى قوله: {فكلوا مما غنمتم حللا طيبا} [ الأنفال: ٦٩] فأحل الله الغنيمة لهم.