Sunan Ibn Majah
886
Hasan Sahih+3

Ahmar, the Companion of the Messenger of Allah (ﷺ), narrated to us:“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.”

Hasan SahihAl-Albani
Hasan SahihMuhammad Fouad Abd al-Baqi