Arabic hadith text
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، زَوْجِ النَّبِيِّ صلى الله عليه وسلم أَنَّهَا أَخْبَرَتْهُ أَنَّهَا لَمْ تَرَ رَسُولَ اللَّهِ صلى الله عليه وسلم يُصَلِّي صَلاَةَ اللَّيْلِ قَاعِدًا قَطُّ حَتَّى أَسَنَّ فَكَانَ يَقْرَأُ قَاعِدًا حَتَّى إِذَا أَرَادَ أَنْ يَرْكَعَ قَامَ فَقَرَأَ نَحْوًا مِنْ ثَلاَثِينَ أَوْ أَرْبَعِينَ آيَةً ثُمَّ رَكَعَ ‏.‏
Translation

Yahya related to me from Malik from Hisham ibn Urwa from hisfather that A'isha, the wife of the Prophet, may Allah bless him andgrant him peace, told him that she had never seen the Messenger ofAllah, may Allah bless him and grant him peace, doing night prayerssitting down until he was getting on in years. He would recite sittingdown until when he wanted to go into ruku, he would stand up andrecite about thirty or forty ayats and then go into ruku.