Narrated Sahl bin Sa`d: The people were ordered to place the right hand on the left forearm in the prayer. Abu Hazim said, "I knew that the order was from the Prophet ."
Hadith Referenceصحيح البخاري / كتاب الأذان (صفة الصلوة) / 740
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة