He heard the Messenger of Allah ﷺ say, "When a servant prostrates, seven parts of his body prostrate with him, his face, his two hands, his two knees, and his two feet."
أخبرنا قتيبة قال حدثنا بكر عن ابن الهاد عن محمد بن إبراهيم عن عامر بن سعد
أنه سمع رسول الله ﷺ يقول إذا سجد العبد سجد منه سبعة آراب وجهه وكفاه وركبتاه وقدماه
Muslim included it in the Book of Prayer, chapter on the limbs of sujud and the prohibition of holding back one's hair, etc., no. 491, from Qutayba, with this wording. It is also found in Kubra, no. 819.