She reported that she never saw the Messenger of Allah ﷺ perform the night prayer while sitting until he grew old. When he became elderly, he would recite while seated, and when he wished to bow, he would stand up and recite about thirty or forty more verses, then bow.
أنها أخبرت: أنها لم تر رسول الله ﷺ يصلي صلاة الليل قاعدا قط حتى أسن، فكان يقرأ قاعدا. حتى إذا أراد أن يركع قام فقرأ نحوا من ثلاثين، أو أربعين آية. ثم ركع.
Malik narrated it in the chapter on congregational prayer (22), from Hisham bin Urwa, from his father, from Ayesha, and she related the same. Bukhari narrated it in the chapter on shortening the prayer (1118) through the route of Malik, with the same wording.He also narrated it (1148), and Muslim narrated it in the chapter on the prayer of the traveler (731), through the route of Yahya bin Saeed, from Hisham bin Urwa, from his father, from her, who said, "I never saw the Messenger of Allah ﷺ recite anything during the night prayer while sitting, except when he grew older, when he would recite while sitting, until when there remained thirty or forty verses of the surah, he would stand and recite them, then bow."Malik also narrated it (23) from Abdullah bin Yazid Madani, and from Abu Nadr, from Abu Salama bin Abdul-Rahman, from Ayesha, who said, "The Messenger of Allah ﷺ used to pray sitting, reciting while seated, and when about thirty or forty verses of his recitation remained, he would stand and recite while standing, then bow and prostrate, then he would do the same in the second rakat."Bukhari narrated it (1119) from Abdullah bin Yusuf, and Muslim (112/731) from Yahya bin Yahya, both of them from Malik, with the same wording.The hadiths of these two chapters indicate the permissibility of both practices, that one may begin standing and bow standing, or begin sitting and bow either sitting or standing, so there is no contradiction between the two practices. All of this pertains to voluntary prayer. And Allah knows best.