(39) باب ذِكْرِ الاِخْتِلاَفِ عَلَى حَبِيبِ بْنِ أَبِي ثَابِتٍ فِي حَدِيثِ ابْنِ عَبَّاسٍ فِي الْوَتْرِ . ج }
It was narrated that 'Aishah said:
"The Messenger of Allah (ﷺ) used to pray nine (rak'ahs) at night, then when he grew older and put on weight he prayed seven."
Reference: Sunan an-Nasa'i 1709
In-book reference: Book 20, Hadith 112
English translation: Vol. 2, Book 20, Hadith 1709