Lu'lu' wal-Marjan

Sayyiduna Anas bin Malik (may Allah be pleased with him) narrated that the Noble Prophet (peace and blessings be upon him) fell from a horse and his right side was injured due to this fall. So we came to visit him to inquire about his health. Meanwhile, the time for prayer arrived and he led us in prayer while sitting, so we also sat down. When he finished the prayer, he said: "The Imam is appointed so that he may be followed. Therefore, when he says the takbir, you should also say the takbir; when he bows (in ruku‘), you should also bow; when he raises his head, you should also raise your heads; and when he says 'Sami‘ Allahu liman hamidah,' you should say 'Rabbana wa lakal hamd'; and when he prostrates, you should also prostrate."