Sahih al-Bukhari 1148
Book 19: Prayer at Night (Tahajjud) · Narrated by `Aisha
Arabic
حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ، عَنْ هِشَامٍ، قَالَ أَخْبَرَنِي أَبِي، عَنْ عَائِشَةَ ـ رضى الله عنها ـ قَالَتْ مَا رَأَيْتُ النَّبِيَّ صلى الله عليه وسلم يَقْرَأُ فِي شَىْءٍ مِنْ صَلاَةِ اللَّيْلِ جَالِسًا، حَتَّى إِذَا كَبِرَ قَرَأَ جَالِسًا، فَإِذَا بَقِيَ عَلَيْهِ مِنَ السُّورَةِ ثَلاَثُونَ أَوْ أَرْبَعُونَ آيَةً قَامَ فَقَرَأَهُنَّ ثُمَّ رَكَعَ.
English translation
Narrated `Aisha:I did not see the Prophet (ﷺ) reciting (the Qur'an) in the night prayer while sitting except when he became old; when he used to recite while sitting, and when thirty or forty verses remained from the Sura, he would get up and recite them and then bow
Reference: Sahih al-Bukhari 1148, Book of Prayer at Night (Tahajjud). English translation by Dr. Muhammad Muhsin Khan.