Hadith 1752

Abu Hurairah (May Allah be pleased with him) said: We are prohibited from placing the hand on the side during As-Salat (the prayer).

[Al-Bukhari and Muslim].

- عن أبي هريرة رضي الله عنه أن رسول الله صلى الله عليه وسلم‏:‏ نهى عن الخصر في الصلاة‏.‏ ‏(‏‏(‏متفق عليه‏)‏‏)‏‏.‏

Reference: 1717420
In-book reference: Book 17, Hadith 1752
Hadith 1752 - The Book of the Prohibited actions - Riyad as-Salihin - Sunnah.com