Sunan an-Nasa'i #1779 · The Book of Qiyam Al-Lail (The Night Prayer) and Voluntary Prayers During the Day

Sunan an-Nasa'iIt was narrated from Salim that his father said
Sunan an-Nasa'i · Book 20 · The Book of Qiyam Al-Lail (The Night Prayer) and Voluntary Prayers During the Day
Sunan an-Nasa'i · كتاب 20 · كتاب قيام الليل وتطوع النهار
"Hafsah told me that when dawn glowed, the Messenger of Allah (ﷺ) would pray two rak'ahs
أَخْبَرَنَا الْحُسَيْنُ بْنُ عِيسَى، قَالَ حَدَّثَنَا سُفْيَانُ، عَنْ عَمْرٍو، عَنِ الزُّهْرِيِّ، عَنْ سَالِمٍ، عَنْ أَبِيهِ، قَالَ أَخْبَرَتْنِي حَفْصَةُ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ إِذَا أَضَاءَ لَهُ الْفَجْرُ صَلَّى رَكْعَتَيْنِ ‏.‏
Reference : Sunan an-Nasa'i 1779In-book reference : Book 20, Hadith 182