Yahya related to me from Malik from Hisham ibn Urwa from hisfather that A'isha, the wife of the Prophet, may Allah bless him andgrant him peace, said, "The Messenger of Allah, may Allah bless himand grant him peace, prayed while he was ill. He prayed sitting, andsome people prayed behind him standing, and he indicated to them tosit down. When he left, he said, 'The imam is only appointed to befollowed. When he goes into ruku, go into ruku and when he rises, riseand if he prays sitting, pray sitting .' "
App reference: Book 8, Hadith 18
USC-MSA web (English) reference: Book 8, Hadith 18
Arabic reference: Book 8, Hadith 307