Messenger of Allah ﷺ rode a horse and fell down and the right side of his body was injured. On that day he prayed one of the prayers sitting and we also prayed behind him sitting. When the Prophet ﷺ finished the prayer with Taslim, he said, "The Imam is to be followed and if he prays standing then pray standing, and bow when he bows, and raise your heads when he raises his head; prostrate when he prostrates; and if he says "Samiʿa l-lahu liman hamidah", you should say, "Rabbana wa laka l-hamd.:
أَنَّ رَسُولَ اللَّهِ ﷺ رَكِبَ فَرَسًا فَجُحِشَ شِقُّهُ الأَيْمَنُ قَالَ أَنَسٌ ؓ فَصَلَّى لَنَا يَوْمَئِذٍ صَلاَةً مِنَ الصَّلَوَاتِ وَهْوَ قَاعِدٌ فَصَلَّيْنَا وَرَاءَهُ قُعُودًا ثُمَّ قَالَ لَمَّا سَلَّمَ إِنَّمَا جُعِلَ الإِمَامُ لِيُؤْتَمَّ بِهِ فَإِذَا صَلَّى قَائِمًا فَصَلُّوا قِيَامًا وَإِذَا رَكَعَ فَارْكَعُوا وَإِذَا رَفَعَ فَارْفَعُوا وَإِذَا سَجَدَ فَاسْجُدُوا وَإِذَا قَالَ سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ فَقُولُوا رَبَّنَا وَلَكَ الْحَمْدُ