Sunan an-Nasa'i 1200

It was narrated that Jabir said:"The Messenger of Allah (ﷺ) was ill, and we prayed behind him while he was sitting, and Abu Bakr repeated his takbirs so that the people could hear them. He turned to us and saw us standing, so he gestured to us to sit down. So we prayed behind him sitting. When he said the salam he said: 'Just now you were doing what the Persians and Romans do for their kings when they are sitting. Do not do that. Follow your Imams: If they pray standing then pray standing, and if they pray sitting then pray sitting