Sahih al-Bukhari 2991

It is related that Anas said, "The Prophet, may Allah bless him and grant him peace, reached Khaybar in the morning and they had come out with their spades on their shoulders. When they saw him, they said, 'This is Muhammad and the army! Muhammad and the army!' They took refuge in their fortress. The Prophet, may Allah bless him and grant him peace, raised his hands and said, 'Allah is greater! Khaybar is ruined. When we alight in the courtyard of a people, it is an evil morning for those who have been warned!' We found some donkeys and cooked them. Then the announcer of the Prophet, may Allah bless him and grant him peace, announced, 'Allah and His Messenger have forbidden you the meat of donkeys!' so the pots were overturned with what was in them." 'Ali corroborated it from Sufyan, "The Prophet, may Allah bless him and grant him peace, raised his hands."