Messenger of Allah ﷺ fell from a horse and the right side of his body was injured. We went to inquire about his health meanwhile it was time for the prayer and he led the prayer sitting and we also prayed while sitting. On completion of the prayer he said, "The Imam is to be followed; say Takbir when he says it; bow when he bows; rise when he rises and when he says "Samiʿa l-lahu liman hamidah," say, "Rabbana wa laka l-hamd", and prostrate if he prostrates." Sufyan narrated the same from Maʿmar. Ibn Juraij said that his (the Prophet's) right leg had been injured.  

سَمِعْتُ أَنَسَ بْنَ مَالِكٍ يَقُولُ سَقَطَ رَسُولُ اللَّهِ ﷺ عَنْ فَرَسٍ وَرُبَّمَا قَالَ سُفْيَانُ مِنْ فَرَسٍ فَجُحِشَ شِقُّهُ الأَيْمَنُ فَدَخَلْنَا عَلَيْهِ نَعُودُهُ فَحَضَرَتِ الصَّلاَةُ فَصَلَّى بِنَا قَاعِدًا وَقَعَدْنَا وَقَالَ سُفْيَانُ مَرَّةً صَلَّيْنَا قُعُودًا فَلَمَّا قَضَى الصَّلاَةَ قَالَ إِنَّمَا جُعِلَ الإِمَامُ لِيُؤْتَمَّ بِهِ فَإِذَا كَبَّرَ فَكَبِّرُوا وَإِذَا رَكَعَ فَارْكَعُوا وَإِذَا رَفَعَ فَارْفَعُوا وَإِذَا قَالَ سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ فَقُولُوا رَبَّنَا وَلَكَ الْحَمْدُ وَإِذَا سَجَدَ فَاسْجُدُوا قَالَ سُفْيَانُ كَذَا جَاءَ بِهِ مَعْمَرٌ قُلْتُ نَعَمْ قَالَ لَقَدْ حَفِظَ كَذَا قَالَ الزُّهْرِيُّ وَلَكَ الْحَمْدُ حَفِظْتُ مِنْ شِقِّهِ الأَيْمَنِ فَلَمَّا خَرَجْنَا مِنْ عِنْدِ الزُّهْرِيِّ قَالَ ابْنُ جُرَيْجٍ وَأَنَا عِنْدَهُ فَجُحِشَ سَاقُهُ الأَيْمَنُ  

the mother of the believers: Messenger of Allah ﷺ during his illness prayed at his house while sitting whereas some people prayed behind him standing. The Prophet ﷺ beckoned them to sit down. On completion of the prayer, he said, 'The Imam is to be followed: bow when he bows, raise up your heads (stand erect) when he raises his head and when he says, 'Samiʿa l-lahu liman hamidah' (Allah heard those who sent praises to Him) say then 'Rabbana wa laka l-hamd' (O our Lord! All the praises are for You), and if he prays sitting then pray sitting."  

أَنَّهَا قَالَتْ صَلَّى رَسُولُ اللَّهِ ﷺ فِي بَيْتِهِ وَهْوَ 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  

The Prophet ﷺ said, "The Imam is to be followed. Say the Takbir when he says it; bow if he bows; if he says 'Samiʿa l-lahu liman hamidah', say, ' Rabbana wa laka l-hamd', prostrate if he prostrates and pray sitting altogether if he prays sitting."  

قَالَ النَّبِيُّ ﷺ إِنَّمَا جُعِلَ الإِمَامُ لِيُؤْتَمَّ بِهِ فَإِذَا كَبَّرَ فَكَبِّرُوا وَإِذَا رَكَعَ فَارْكَعُوا وَإِذَا قَالَ سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ فَقُولُوا رَبَّنَا وَلَكَ الْحَمْدُ وَإِذَا سَجَدَ فَاسْجُدُوا وَإِذَا صَلَّى جَالِسًا فَصَلُّوا جُلُوسًا أَجْمَعُونَ