Sunan an-Nasa'i 833
It was narrated that Aisha said:
"When the Messenger of Allah (ﷺ) became seriously ill, Bilal came to tell him it was time to pray and he said: 'Tell Abu Bakr to lead the people in prayer."' She said: "I said: '0 Messenger of Allah (ﷺ), Abu Bakr is a tender-hearted man, and when he stands in your place he will not be able to make the people 
hear his voice; why don't you tell 'Umar (to do it)?' He said: 'Tell a Abu Bakr to lead the people in the prayer.' I said to Hafsah: 'Tell him.' So she told him. He said: 'You are (like) the female companions of Yosuf. Tell Abu Bakr lead the people in prayer."' She said: "So they told Abu Bakr. When he started to pray, the Messenger of Allah (ﷺ) began to feel better, so he got up and came with the help of two men, with his feet dragging along the ground. (When) he entered the Masjid, Abu
Bakr heard him coming and he wanted to step back, but the Messenger of Allah (ﷺ) gestured to him: 'Stay where you are.' Then the Messenger of Allah (ﷺ) came and sat on Abu Bakr's left, so the Messenger of Allah (ﷺ) was leading the people in prayer sitting, and Abu Bakr was standing and following the Messenger of Allah (ﷺ) and the people were following the prayer of Abu Bakr, may Allah be pleased with him."
أَخْبَرَنَا مُحَمَّدُ بْنُ الْعَلاَءِ، قَالَ حَدَّثَنَا أَبُو مُعَاوِيَةَ، عَنِ الأَعْمَشِ، عَنْ إِبْرَاهِيمَ، عَنِ الأَسْوَدِ، عَنْ عَائِشَةَ، قَالَتْ لَمَّا ثَقُلَ رَسُولُ اللَّهِ صلى الله عليه وسلم جَاءَ بِلاَلٌ يُؤْذِنُهُ بِالصَّلاَةِ فَقَالَ ‏"‏ مُرُوا أَبَا بَكْرٍ فَلْيُصَلِّ بِالنَّاسِ ‏"‏ ‏.‏ قَالَتْ قُلْتُ يَا رَسُولَ اللَّهِ إِنَّ أَبَا بَكْرٍ رَجُلٌ أَسِيفٌ وَإِنَّهُ مَتَى يَقُومُ فِي مَقَامِكَ لاَ يُسْمِعُ النَّاسَ فَلَوْ أَمَرْتَ عُمَرَ ‏.‏ فَقَالَ ‏"‏ مُرُوا أَبَا بَكْرٍ فَلْيُصَلِّ بِالنَّاسِ ‏"‏ ‏.‏ فَقُلْتُ لِحَفْصَةَ قُولِي لَهُ فَقَالَتْ لَهُ ‏.‏ فَقَالَ ‏"‏ إِنَّكُنَّ لأَنْتُنَّ صَوَاحِبَاتُ يُوسُفَ مُرُوا أَبَا بَكْرٍ فَلْيُصَلِّ بِالنَّاسِ ‏"‏ ‏.‏ قَالَتْ فَأَمَرُوا أَبَا بَكْرٍ فَلَمَّا دَخَلَ فِي الصَّلاَةِ وَجَدَ رَسُولُ اللَّهِ صلى الله عليه وسلم مِنْ نَفْسِهِ خِفَّةً - قَالَتْ - فَقَامَ يُهَادَى بَيْنَ رَجُلَيْنِ وَرِجْلاَهُ تَخُطَّانِ فِي الأَرْضِ فَلَمَّا دَخَلَ الْمَسْجِدَ سَمِعَ أَبُو بَكْرٍ حِسَّهُ فَذَهَبَ لِيَتَأَخَّرَ فَأَوْمَأَ إِلَيْهِ رَسُولُ اللَّهِ صلى الله عليه وسلم أَنْ قُمْ كَمَا أَنْتَ قَالَتْ فَجَاءَ رَسُولُ اللَّهِ صلى الله عليه وسلم حَتَّى قَامَ عَنْ يَسَارِ أَبِي بَكْرٍ جَالِسًا فَكَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يُصَلِّي بِالنَّاسِ جَالِسًا وَأَبُو بَكْرٍ قَائِمًا يَقْتَدِي أَبُو بَكْرٍ بِرَسُولِ اللَّهِ صلى الله عليه وسلم وَالنَّاسُ يَقْتَدُونَ بِصَلاَةِ أَبِي بَكْرٍ رضى الله عنه ‏.‏