Musnad Abu Ya'la al-Mawsili 111:21

Abu Ya'la narrated to us, 'Amr ibn Malik narrated to us, 'Abd al-Rahman ibn 'Uthman Abu Bahr al-Bakrawi narrated to us, Bahr ibn Murar narrated to us, from his grandfather 'Abd al-Rahman ibn Abi Bakrah, from his father, who said: I saw the Messenger of Allah, may Allah bless him and grant him peace, praying in his sandals.