Musannaf Ibn Abi Shayba 36:343

Yazid ibn Harun narrated to us, he said: Ibn 'Awn informed us, from 'Amr ibn Sa'id, from Abu Talha, who said: I was riding behind the Prophet, may Allah bless him and grant him peace, on the day of Khaybar. When we arrived, they had come out with their shovels. When they saw us, they said: "Muhammad! By Allah, and the army!" The Messenger of Allah, may Allah bless him and grant him peace, said: "Allah is the Greatest. Indeed, when we descend into the courtyard of a people, then evil is the morning of those who have been warned."