Sayyiduna Ahmar (may Allah be pleased with him) says that we used to feel pity for the Messenger of Allah (peace and blessings be upon him) because of how far he (peace and blessings be upon him) kept his hands away from his sides during prostration.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2711
Hadith Gradingمحدثین:صحيح
Hadith Takhrij«صحيح۔ اخرجه ابن سعد 7/ 47۔ في الطبقات، وابن ابي شيبة 2641»