When Allah granted His Messenger the conquest of Mecca, he stood before the people, praised Allah and glorified Him, then said, "Its lost property may not be picked up except by one who will announce it publicly."
لما فتح الله على رسوله مكة، فقام في الناس، فحمد الله، وأثنى عليه، ثم قال: ولا تحل ساقطتها إلا لمنشد.
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 bin Abdul-Rahman narrated to me, who said, Abu Hurairah narrated to me, and he related it in a long hadith.