Hadith 731

'A'isha reported: The Messenger of Allah (may peace be upon him) used to pray while sitting (when he grew old) and he recited in this position and when the recitation equal to thirty or forty verses was left, he would then stand up and recite (for this duration) in a standing position and then bowed himself and then prostrated himself and did the same in the second rak'ah.

وَحَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنْ عَبْدِ اللَّهِ بْنِ يَزِيدَ، وَأَبِي النَّضْرِ، عَنْ أَبِي سَلَمَةَ بْنِ عَبْدِ الرَّحْمَنِ، عَنْ عَائِشَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يُصَلِّي جَالِسًا فَيَقْرَأُ وَهُوَ جَالِسٌ فَإِذَا بَقِيَ مِنْ قِرَاءَتِهِ قَدْرُ مَا يَكُونُ ثَلاَثِينَ أَوْ أَرْبَعِينَ آيَةً قَامَ فَقَرَأَ وَهُوَ قَائِمٌ ثُمَّ رَكَعَ ثُمَّ سَجَدَ ثُمَّ يَفْعَلُ فِي الرَّكْعَةِ الثَّانِيَةِ مِثْلَ ذَلِكَ ‏.‏

Reference: 317400
In-book reference: Book 6, Hadith 731 b
Hadith 731 - The Book of Mosques and Places of Prayer - Sahih Muslim - Sunnah.com