Musannaf Ibn Abi Shayba 3:5522

Shababa narrated to us, he said: Ibn Abi Dhi'b narrated to us, from al-Maqburi, from his father, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "When one of you prays, let him place his sandals between his feet."