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."

أَخْبَرَنَا أَبُو عَاصِمٍ، خُشَيْشُ بْنُ أَصْرَمَ قَالَ حَدَّثَنَا يَحْيَى بْنُ حَسَّانَ، قَالَ حَدَّثَنَا حَمَّادُ بْنُ سَلَمَةَ، عَنْ عَمْرِو بْنِ دِينَارٍ، عَنْ نَافِعِ بْنِ جُبَيْرٍ، عَنْ أَبِيهِ، أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ فِي سَفَرٍ لَهُ " مَنْ يَكْلَؤُنَا اللَّيْلَةَ لاَ نَرْقُدَ عَنْ صَلاَةِ الصُّبْحِ " . قَالَ بِلاَلٌ أَنَا . فَاسْتَقْبَلَ مَطْلَعَ الشَّمْسِ فَضُرِبَ عَلَى آذَانِهِمْ حَتَّى أَيْقَظَهُمْ حَرُّ الشَّمْسِ فَقَامُوا فَقَالَ " تَوَضَّئُوا " . ثُمَّ أَذَّنَ بِلاَلٌ فَصَلَّى رَكْعَتَيْنِ وَصَلَّوْا رَكْعَتَىِ الْفَجْرِ ثُمَّ صَلَّوُا الْفَجْرَ .