Yahya related to me from Malik from Ibn Shihab from Anas ibn Malik that the Messenger of Allah ﷺ fell off his horse when riding, and his right side was scraped, so he did one of the prayers sitting, and we prayed behind him sitting. When he left, he said, "The imam is appointed to be followed. If he prays standing, then pray standing, and when he goes into ruku, go into ruku, and when he rises, rise, and when he says, 'Allah hears whoever praises him,' say, 'Our Lord, praise belongs to You,' and if he prays sitting, then all of you pray sitting."  

أَنَّ رَسُولَ اللَّهِ ﷺ رَكِبَ فَرَسًا فَصُرِعَ فَجُحِشَ شِقُّهُ الأَيْمَنُ فَصَلَّى صَلاَةً مِنَ الصَّلَوَاتِ وَهُوَ قَاعِدٌ وَصَلَّيْنَا وَرَاءَهُ قُعُودًا فَلَمَّا انْصَرَفَ قَالَ إِنَّمَا جُعِلَ الإِمَامُ لِيُؤْتَمَّ بِهِ فَإِذَا صَلَّى قَائِمًا فَصَلُّوا قِيَامًا وَإِذَا رَكَعَ فَارْكَعُوا وَإِذَا رَفَعَ فَارْفَعُوا وَإِذَا قَالَ سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ فَقُولُوا رَبَّنَا وَلَكَ الْحَمْدُ وَإِذَا صَلَّى جَالِسًا فَصَلُّوا جُلُوسًا أَجْمَعُونَ  

Yahya related to me from Malik from Hisham ibn Urwa from his father that A'isha, the wife of the Prophet ﷺ said, "The Messenger of Allah ﷺ prayed while he was ill. He prayed sitting, and some people prayed behind him standing, and he indicated to them to sit down. When he left, he said, 'The imam is only appointed to be followed. When he goes into ruku, go into ruku and when he rises, rise and if he prays sitting, pray sitting .' "  

عَنْ عَائِشَةَ زَوْجِ النَّبِيِّ ﷺ أَنَّهَا قَالَتْ صَلَّى رَسُولُ اللَّهِ ﷺ وَهُوَ شَاكٍ فَصَلَّى جَالِسًا وَصَلَّى وَرَاءَهُ قَوْمٌ قِيَامًا فَأَشَارَ إِلَيْهِمْ أَنِ اجْلِسُوا فَلَمَّا انْصَرَفَ قَالَ إِنَّمَا جُعِلَ الإِمَامُ لِيُؤْتَمَّ بِهِ فَإِذَا رَكَعَ فَارْكَعُوا وَإِذَا رَفَعَ فَارْفَعُوا وَإِذَا صَلَّى جَالِسًا فَصَلُّوا جُلُوسًا  

Yahya related to me from Malik from Hisham ibn Urwa from his father that the Messenger of Allah ﷺ came out during his illness, and approached and found Abu Bakr standing, leading the people in prayer. Abu Bakr began to go back, but the Messenger of Allah ﷺ indicated to him to stay where he was. The Messenger of Allah ﷺ sat by the side of Abu Bakr, and Abu Bakr prayed following the prayer of the Messenger of Allah ﷺ who was sitting, and the people prayed following the prayer of Abu Bakr.  

أَنَّ رَسُولَ اللَّهِ ﷺ خَرَجَ فِي مَرَضِهِ فَأَتَى فَوَجَدَ أَبَا بَكْرٍ وَهُوَ قَائِمٌ يُصَلِّي بِالنَّاسِ فَاسْتَأْخَرَ أَبُو بَكْرٍ فَأَشَارَ إِلَيْهِ رَسُولُ اللَّهِ ﷺ أَنْ كَمَا أَنْتَ فَجَلَسَ رَسُولُ اللَّهِ ﷺ إِلَى جَنْبِ أَبِي بَكْرٍ فَكَانَ أَبُو بَكْرٍ يُصَلِّي بِصَلاَةِ رَسُولِ اللَّهِ ﷺ وَهُوَ جَالِسٌ وَكَانَ النَّاسُ يُصَلُّونَ بِصَلاَةِ أَبِي بَكْرٍ