Musnad Ahmad 30:2407

Yahya ibn Sa'id narrated to us, from Yazid ibn Kaysan, who said: Abu Hazim narrated to me, from Abu Hurayrah, who said: We camped with the Prophet of Allah, may Allah bless him and grant him peace, and we did not wake up until the sun had risen. The Messenger of Allah, may Allah bless him and grant him peace, said: "Let every man take hold of the head of his mount, for this is a place where the devil has attended us." He said: So we did that. He said: Then he called for water and performed ablution, then he prayed two rak'ahs before the morning prayer. Then the prayer was called, and he prayed the morning prayer.