Sunan An-Nasai, Chapter: The Book of the Times (of Prayer)

that his father said: "We were with the Messenger of Allah (saw) on a journey, and we kept going one night, then when it was nearly morning the Messenger of Allah (saw) dismounted and slept, and the people slept too. We did not wake up until the sun had risen. The Messenger of Allah (saw) asked the Mu'adhdhin to call the Adhan, then he prayed the two Rakahs before Fajr, then he asked him to say the Iqamah, then he led the people in prayer. Then he told us about everything that will happen until the Hour begins." (Hasan)