Sahih Bukhari Volume 3, Book 38, Hadith Number 503.
Narated By Marwan bin Al-Hakam and Al-Miswar bin Makhrama : When the delegates of the tribe of Hawazin after embracing Islam, came to Allah’s Apostle, he got up. They appealed to him to return their properties and their captives. Allah’s Apostle said to them, “The most beloved statement to me is the true one. So, you have the option of restoring your properties or your captives, for I have delayed distributing them.” The narrator added, Allah’s Apostle c had been waiting for them for more than ten days on his return from Taif. When they realized that Allah’s Apostle would return to them only one of two things, they said, “We choose our captives.” So, Allah’s Apostle got up in the gathering of the Muslims, praised Allah as He deserved, and said, “Then after! These brethren of yours have come to you with repentance and I see it proper to return their captives to them. So, whoever amongst you likes to do that as a favor, then he can do it, and whoever of you wants to stick to his share till we pay him from the very first booty which Allah will give us then he can do so.” The people replied, “We agree to give up our shares willingly as a favor for Allah’s Apostle.” Then Allah’s Apostle said, “We don’t know who amongst you has agreed and who hasn’t. Go back and your chiefs may tell us your opinion.” So, all of them returned and their chiefs discussed the matter with them and then they (i.e. their chiefs) came to Allah’s Apostle to tell him that they (i.e. the people) had given up their shares gladly and willingly.