Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi)

Bukhari :: Book 5 :: Volume 59 :: Hadith 510

Narrated Anas:

Allah's Apostle reached Khaibar at night and it was his habit that, whenever he reached the enemy at night, he will not attack them till it was morning. When it was morning, the Jews came out with their spades and baskets, and when they saw him(i.e. the Prophet ), they said, "Muhammad! By Allah! Muhammad and his army!" The Prophet said, "Khaibar is destroyed, for whenever we approach a (hostile) nation (to fight), then evil will be the morning for those who have been warned."

Narrated Anas bin Malik: We reached Khaibar early in the morning and the inhabitants of Khaibar came out carrying their spades, and when they saw the Prophet they said, "Muhammad! By Allah! Muhammad and his army!" The Prophet said, "Allahu-Akbar! Khaibar is destroyed, for whenever we approach a (hostile) nation (to fight) then evil will be the morning for those who have been warned." We then got the meat of donkeys (and intended to eat it), but an announcement was made by the announcer of the Prophet, "Allah and His Apostle forbid you to eat the meat of donkeys as it is an impure thing."