Sunan an-Nasa'i #1777 · The Book of Qiyam Al-Lail (The Night Prayer) and Voluntary Prayers During the Day

Sunan an-Nasa'iIt was narrated from Ibn Umar
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
When the call to Subh prayer was given, the Messenger of Allah (ﷺ) would pray two brief rak'ahs before going to pray
أَخْبَرَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، قَالَ حَدَّثَنَا اللَّيْثُ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، عَنْ حَفْصَةَ، عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم أَنَّهُ كَانَ إِذَا نُودِيَ لِصَلاَةِ الصُّبْحِ رَكَعَ رَكْعَتَيْنِ خَفِيفَتَيْنِ قَبْلَ أَنْ يَقُومَ إِلَى الصَّلاَةِ ‏.‏ وَرَوَى سَالِمٌ عَنِ ابْنِ عُمَرَ عَنْ حَفْصَةَ ‏.‏
Reference : Sunan an-Nasa'i 1777In-book reference : Book 20, Hadith 180