Abdullah bin Wahb عبد الله بن وهب بن مسلم القرشي · The Book of the Times (of Prayer)

"If the Messenger of Allah (ﷺ) was in a hurry to travel, or some emergency arose, he would combine Maghrib and 'Isha'."

"Who will watch out for dawn for us, so that we do not sleep and miss the dawn prayer?" Bilal said: 'I will.' He turned to face the direction where the sun woke them up, then they got up. He said: 'Perform Wudu'.' Then Bilal called the Adhan and he prayed two Rak'ahs, and they prayed the two (Sunnah) Rak'ahs of Fajr, then they prayed Fajr."