Sunan An-Nasa'i - سنن النسائي
20. The Book of Qiyam Al-Lail (The Night Prayer) and Voluntary Prayers During the Day - كتاب قيام الليل وتطوع النهار
19) Chapter: Sitting while performing voluntary prayers, and mentioning the differences reported from Abu Ishaq regarding that
It was narrated that Hafsah said:
"I never saw the Messenger of Allah (ﷺ) offer his voluntary prayers sitting down until one year before his death. Then he used to pray sitting down, reciting the surah so slowly that it seemed to be longer than a surah that is longer."
19) باب صَلاَةِ الْقَاعِدِ فِي النَّافِلَةِ وَذِكْرِ الاِخْتِلاَفِ عَلَى أَبِي إِسْحَاقَ فِي ذَلِكَ
أَخْبَرَنَا قُتَيْبَةُ، عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، عَنِ السَّائِبِ بْنِ يَزِيدَ، عَنِ الْمُطَّلِبِ بْنِ أَبِي وَدَاعَةَ، عَنْ حَفْصَةَ، قَالَتْ مَا رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم صَلَّى فِي سُبْحَتِهِ قَاعِدًا قَطُّ حَتَّى كَانَ قَبْلَ وَفَاتِهِ بِعَامٍ فَكَانَ يُصَلِّي قَاعِدًا يَقْرَأُ بِالسُّورَةِ فَيُرَتِّلُهَا حَتَّى تَكُونَ أَطْوَلَ مِنْ أَطْوَلَ مِنْهَا .
