The Messenger of Allah ﷺ prayed in his house while he was ill, so he prayed sitting down, and a group of people prayed behind him standing. He gestured to them to sit down. When he finished, he said, "The imam is appointed only to be followed. So when he bows, bow, when he rises, rise, and when he prays sitting, pray sitting."
قال قرأت على عبد الرحمن: مالك عن هشام بن عروة عن أبيه
صلى رسول الله ﷺ في بيته وهو شاك فصلى جالسا وصلى وراءه قوم قياما فأشار إليهم أن اجلسوا فلما انصرف قال إنما جعل الإمام ليؤتم به فإذا ركع فاركعوا وإذا رفع فارفعوا وإذا صلى جالسا فصلوا جلوسا