(Imām Bukhārī narrates): 'Abdullāh ibn Yūsuf narrated to us, he said: Imām Mālik informed us, from Hishām ibn 'Urwah, from his father, from 'Ā'ishah, Umm al-Mu'minīn, may Allāh be pleased with her, she narrates that:

the Messenger of Allāh ﷺ prayed in his house; at that time he was ill, so he prayed sitting, and the people behind him prayed standing. He gestured to them that they should sit. When he finished the prayer, he said: The imām is appointed only so that he may be followed; so when he performs rukū', you perform rukū', and when he raises his head from rukū', you raise your head from rukū', and when he says "Sami'a Allāhu liman hamidah", you say "Rabbanā wa laka al-hamd", and when he prays sitting, all of you also pray sitting.