When Allah granted His Messenger the conquest of Mecca, he stood among the people, praised Allah and extolled Him, then said, "...Whoever has had a relative killed has the choice between two options, either to accept blood-money or to demand retaliation."
لما فتح الله على رسوله مكة قام في الناس، فحمد الله وأثنى عليه ثم قال: … ومن قتل له قتيل فهو بخير النظرين: إما أن يفدى وإما أن يقيد.
Bukhari narrated it in the Book of Lost Property (2434), and Muslim in the Book of Hajj (1355), both from the hadith of Walid bin Muslim, who said, Uzai narrated to us, who said, Yahya bin Abu Kathir narrated to me, who said, Abu Salama narrated to me, who said, Abu Hurairah narrated to me, and he related it.