“The Messenger of Allah ﷺ fell ill, and we prayed behind him while he was sitting down, and Abu Bakr was saying the Takbir so that the people could hear them. He turned to us and saw us standing, so he gestured to us to sit down. When he had said the Salam, he said: ‘You were about to do the action of the Persians and Romans, who remain standing while their kings are seated. Do not do that. Follow the lead of your Imam; if he prays standing, then pray standing, and if he prays sitting down, then pray sitting down.’” (Using translation from Ibn Mājah 1240)  

أَنَّهُ قَالَ اشْتَكَى رَسُولُ اللهِ ﷺ فَصَلَّيْنَا وَرَاءَهُ وَهُوَ قَاعِدٌ وَأَبُو بَكْرٍ يُكَبِّرُ يُسْمَعُ النَّاسُ تَكْبِيرَهُ فَالْتَفَتَ إِلَيْنَا فَرَآنَا قِيَامًا فَأَشَارَ إِلَيْنَا وَقَعَدْنَا فَصَلَّيْنَا بِصَلَاتِهِ قُعُودًا فَلَمَّا سَلَّمَ قَالَ «إِنَّ كِدْتُمْ آنِفًا تَفْعَلُونَ فِعْلَ فَارِسَ وَالرُّومِ يَقُومُونَ عَلَى مُلُوكِهِمْ وَهُمْ قَعُودٌ فَلَا تَفْعَلُوا ائْتَمُّوا بِأَئِمَّتِكُمْ إِنْ صَلَّى قَائِمًا فَصَلَّوْا قِيَامًا وَإِنَّ صَلَّى قَاعِدًا فَصَلَّوْا قُعُودًا»  

"The Messenger of Allah ﷺ used to turn to his right and left when praying, but he did not twist his neck to look behind him." (Using translation from Nasāʾī 1201)  

كَانَ رَسُولُ اللهِ ﷺ «يَلْتَفِتُ فِي صَلَاتِهِ يَمِينًا وَشِمَالًا وَلَا يَلْوِي عُنُقَهُ خَلْفَ ظَهْرِهِ»