It was narrated from Nafi' bin Jubair, from his father, that the Messenger of Allah (ﷺ) said during a journey: "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””
Sahih IsnaadSahih IsnaadIsnaad SahihBook 6 · Hadith 131