The Messenger of Allah ﷺ fell ill, so we prayed behind him while he was seated, and Abu Bakr was relaying his takbir to the people. He turned toward us and saw that we were standing, so he gestured for us to sit down, and we completed the prayer seated as he was praying.When he gave the closing salam, he said, "You were just about to do what the Persians and Romans do, standing before their kings while the kings remain seated. Do not do that. Follow your imams. If he prays standing, then pray standing, and if he prays seated, then pray seated."
اشتكى رسول الله ﷺ فصلينا وراءه وهو قاعد، وأبو بكر يسمع الناس تكبيره. فالتفت إلينا فرآنا قياما، فأشار إلينا فقعدنا، فصلينا بصلاته قعودا، فلما سلم قال: إن كدتم آنفا لتفعلون فعل فارس والروم، يقومون على ملوكهم، وهم قعود، فلا تفعلوا ائتموا بأئمتكم. إن صلى قائما فصلوا قياما، وإن صلى قاعدا فصلوا قعودا.
Muslim narrated it in the Book of Prayer (413) through several routes from Layth bin Saad, from Abu Zubayr, from Jabir, mentioning the same.On this subject there is also the hadith of Ayesha, which Bukhari recorded in the Book of Adhan (688), and Muslim in the Book of Prayer (412), in which it says, "So he gestured to them to sit down," without mentioning the turning around. However, the gesture necessarily implies the turning around, for he only gestured to them to sit because he had turned and seen them standing. This will come later in the chapters on what is permitted in prayer regarding gestures.