Muwatta Imam Malik (Riwayat Ibn al-Qasim)

And with this same chain (it is narrated from Sayyiduna Anas bin Malik, may Allah be pleased with him) that when the Messenger of Allah, peace and blessings be upon him, set out (from Madinah) to conquer Khaybar, he entered there at night. Whenever the Messenger of Allah, peace and blessings be upon him, intended to attack a (hostile) people, he would not attack before morning. Then, when morning came, the Jews came out with their spades and baskets. When they saw the Messenger of Allah, peace and blessings be upon him, they said: "It is Muhammad (peace and blessings be upon him), by Allah! It is Muhammad (peace and blessings be upon him) and his army." So the Messenger of Allah, peace and blessings be upon him, said: "Allah is the Greatest! Khaybar is ruined. When we reach a people, then evil is the morning for those who have been warned (of Hell and punishment)."