يُصَلِّي لَيْلاً طَوِيلاً فَإِذَا صَلَّى قَائِمًا رَكَعَ قَائِمًا وَإِذَا صَلَّى قَاعِدًا رَكَعَ قَاعِدًا .
It was narrated that 'Aishah said: "The Messenger of Allah (ﷺ) used to pray for a long time at night. If he started to pray standing, he would bow standing and if he started to pray sitting, he would bow sitting."