Musnad Ahmad 626:94

Muhammad ibn Rabi‘ah narrated to us, Yunus ibn al-Harith al-Ta’ifi narrated to us, from Abu ‘Awn, from his father, from al-Mughirah ibn Shu‘bah, who said: "The Messenger of Allah (may Allah bless him and grant him peace) used to pray, or he liked to pray, upon a tanned hide."