Book 12: Characteristics of Prayer
Volume 1, Book 12, Number 699: Narrated Anas bin Malik Al-Ansari: Allah's Apostle 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 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 "Sami'a-l-lahu Liman hamida", you should say, "Rabbana wa-laka-l hamd.: Volume 1, Book 12, Number 700: Narrated Anas bin Malik: Allah's Apostle fell from a horse and got injured so he led the prayer sitting and we also prayed sitting. When he completed the prayer he said, "The Imam is to be followed; if he says Takbir then say Takbir, bow if he bows; raise your heads when he raises his head, when he says, 'Sami' a-l-lahu Liman hamida say, '