بُلُوغُ الْمَرَامِ
Bulugh al-Maram 410
The Book of Prayer
وَعَنْ عَائِشَةَ رَضِيَ اَللَّهُ عَنْهَا فِي قِصَّةِ صَلَاةِ رَسُولِ اَللَّهِ - صلى الله عليه وسلم -بِالنَّاسِ, وَهُوَ مَرِيضٌ - قَالَتْ: { فَجَاءَ حَتَّى جَلَسَ عَنْ يَسَارِ أَبِي بَكْرٍ, فَكَانَ يُصَلِّي بِالنَّاسِ جَالِسًا وَأَبُو بَكْرٍ قَائِمًا, يَقْتَدِي أَبُو بَكْرٍ بِصَلَاةِ اَلنَّبِيِّ - صلى الله عليه وسلم -وَيَقْتَدِي اَلنَّاسُ بِصَلَاةِ أَبِي بَكْرٍ } مُتَّفَقٌ عَلَيْه ِ [1] .
Narrated 'Aishah (RA) regarding Allah's Messenger (ﷺ) leading the people in Salat (prayer) during his illness. She said, "He came and sat on the left side of Abu Bakr (RA). So he (ﷺ) was leading the people in prayer while sitting and Abu Bakr standing. Abu Bakr was following the prayer of the Prophet (ﷺ), and the people were following the prayer of Abu Bakr." [Agreed upon].
Sunnah.com reference: Book 2, Hadith 315