Sunan an-Nasa'i #1647 · The Book of Qiyam Al-Lail (The Night Prayer) and Voluntary Prayers During the Day

Sunan an-Nasa'iIt was narrated hat Aishah said
Sunan an-Nasa'i · Book 20 · The Book of Qiyam Al-Lail (The Night Prayer) and Voluntary Prayers During the Day
Sunan an-Nasa'i · كتاب 20 · كتاب قيام الليل وتطوع النهار
"The Messenger of Allah (ﷺ) used to pray standing and sitting. If he started to pray standing, he would bow standing and if he started to pray sitting, he would bow sitting
أَخْبَرَنَا عَبْدَةُ بْنُ عَبْدِ الرَّحِيمِ، قَالَ أَنْبَأَنَا وَكِيعٌ، قَالَ حَدَّثَنِي يَزِيدُ بْنُ إِبْرَاهِيمَ، عَنِ ابْنِ سِيرِينَ، عَنْ عَبْدِ اللَّهِ بْنِ شَقِيقٍ، عَنْ عَائِشَةَ، قَالَتْ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يُصَلِّي قَائِمًا وَقَاعِدًا فَإِذَا افْتَتَحَ الصَّلاَةَ قَائِمًا رَكَعَ قَائِمًا وَإِذَا افْتَتَحَ الصَّلاَةَ قَاعِدًا رَكَعَ قَاعِدًا ‏.‏
Reference : Sunan an-Nasa'i 1647In-book reference : Book 20, Hadith 50