Musannaf Ibn Abi Shayba 17:1377

Abdah ibn Sulayman narrated to us, from Muhammad ibn ‘Amr, from Abu Salamah, from Abu Hurayrah, who said: The Messenger of Allah (may Allah bless him and grant him peace) passed by a man lying prone on his stomach. He said, "Indeed, this is a posture that Allah does not like."