“We used to feel sorry for the Messenger of Allah ﷺ because he took pains to keep his arms away from his sides when he prostrated.” (Using translation from Ibn Mājah 886)
ثنا أَحْمَرُ صَاحِبُ رَسُولِ اللهِ ﷺ قَالَ إِنْ كُنَّا لَنَأْوِي لِرَسُولِ اللهِ ﷺ مِمَّا يُجَافِي بِيَدَيْهِ عَنْ جَنْبَيْهِ إِذَا سَجَدَ