عَنْ حَفْصَةَ زَوْجِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ وَرَضِيَ اللَّهُ عَنْهَا أَنَّهَا قَالَتْ: لَمْ أَرَ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ يُصَلِّي فِي سُبْحَتِهِ جَالِسًا قَطُّ حَتَّى إِذَا كَانَ قَبْلَ مَوْتِهِ بِعَامٍ أَوْ بِعَامَيْنِ فَكَانَ يُصَلِّي فِي سُبْحَتِهِ جَالِسًا وَيَقْرَأُ السُّورَةَ فَيُرَتِّلُهَا حَتَّى تَكُونَ أَطْوَلَ مِنْ أَطْوَلِ مِنْهَا
The wife of the Messenger, Sayyidah Hafsah (may Allah be pleased with her), says: I never saw the Messenger of Allah (peace and blessings be upon him) performing voluntary prayers while sitting, but one or two years before his passing, he (peace and blessings be upon him) began to pray while sitting. He (peace and blessings be upon him) would recite a surah and would recite it so slowly and deliberately that it would become longer and longer.