Ibn Hibban

Sayyiduna Anas bin Malik (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) mounted a horse and fell from it. His right side was injured. Sayyiduna Anas (may Allah be pleased with him) narrates: That day, the Prophet (peace and blessings be upon him) led us in prayer while sitting. We also performed the prayer sitting behind him. When he finished the prayer with salam, he said: "The Imam is appointed so that he may be followed. When the Imam stands to pray, you should also stand and pray. When he goes into ruku, you should also go into ruku. When he raises his head from ruku, you should also raise your heads. When he goes into sajdah, you should also go into sajdah. When he «سَمِعَ اللهُ لِمَنْ حَمِدَہ», you «رَبَّنَا وَلَكَ الْحَمْدُ». When he prays sitting, then all of you should also pray sitting."