Sahih Bukhari Volume 9, Book 93, Hadith 7178

حَدَّثَنَا إِسْمَاعِيلُ بْنُ أَبِي أُوَيْسٍ، حَدَّثَنِي إِسْمَاعِيلُ بْنُ إِبْرَاهِيمَ، عَنْ عَمِّهِ، مُوسَى بْنِ عُقْبَةَ قَالَ ابْنُ شِهَابٍ حَدَّثَنِي عُرْوَةُ بْنُ الزُّبَيْرِ، أَنَّ مَرْوَانَ بْنَ الْحَكَمِ، وَالْمِسْوَرَ بْنَ مَخْرَمَةَ، أَخْبَرَاهُ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ حِينَ أَذِنَ لَهُمُ الْمُسْلِمُونَ فِي عِتْقِ سَبْىِ هَوَازِنَ ‏"‏ إِنِّي لاَ أَدْرِي مَنْ أَذِنَ مِنْكُمْ مِمَّنْ لَمْ يَأْذَنْ، فَارْجِعُوا حَتَّى يَرْفَعَ إِلَيْنَا عُرَفَاؤُكُمْ أَمْرَكُمْ ‏"‏‏.‏ فَرَجَعَ النَّاسُ فَكَلَّمَهُمْ عُرَفَاؤُهُمْ، فَرَجَعُوا إِلَى رَسُولِ اللَّهِ صلى الله عليه وسلم فَأَخْبَرُوهُ أَنَّ النَّاسَ قَدْ طَيَّبُوا وَأَذِنُوا‏.

Narrated By 'Urwa bin Az-Zubair : Marwan bin Al-Hakam and Al-Miswar bin Makhrama told him that when the Muslims were permitted to set free the captives of Hawazin, Allah's Apostle said, "I do not know who amongst you has agreed (to it) and who has not. Go back so that your 'Urafa' may submit your decision to us." So the people returned and their 'Urafa' talked to them and then came back to Allah's Apostle and told him that the people had given their consent happily and permitted (their captives to be freed).