Sahih Bukhari Volume 005, Book 059, Hadith Number 511.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 59. Military Expeditions Led by the Prophet (PBUH) (Al-Maghaazi)
Narrated By Anas bin Malik : Someone came to Allah's Apostles and said, "The donkeys have been eaten (by the Muslims)." The Prophet kept quiet. Then the man came again and said, "The donkeys have been eaten." The Prophet kept quiet. The man came to him the third time and said, "The donkeys have been consumed." On that the Prophet ordered an announcer to announce to the people, "Allah and His Apostle forbid you to eat the meat of donkeys." Then the cooking pots were upset while the meat was still boiling in them.