Sahih Al Bukhari (576)

عن المسور بن مخرمة رضي الله عنهما ومروان أخبراه "أن النبي (صلى الله عليه وسلم) حين جاءه وفد هوازن قام في الناس فأثنى على الله بما هو أهله ثم قال أما بعد فإن إخوانكم جاءونا تائبين وإني رأيت أن أرد إليهم سبيهم فمن أحب منكم أن يطيب ذلك فليفعل ومن أحب أن يكون على حظه حتى نعطيه إياه من أول ما يفيء الله علينا فقال الناس طيبنا لك"

Al-Miswar ibn Makhramah and Marwan narrated: When the delegates of the tribe of Hawazin came to the Prophet (peace be upon him) he stood up amongst the people, Glorified and Praised Allah as He deserved, and said: "Then after: Your brethren have come to you with repentance and I see it logical to return to them their captives; so whoever amongst you likes to do that as a favor, then he can do it, and whoever of you likes to stick to his share till we give him his right from the very first Fai (war booty) (1) which Allah will bestow on us, then (he can do so)." The people replied: "We do that (to return the captives) willingly as a favor for your sake."