Musnad Ahmad 5:36

Abdullah narrated to us, Abu Abd al-Rahman Abdullah ibn Abi Ziyad al-Qatwani narrated to me, Zayd ibn al-Hubab narrated to us, Harb Abu Sufyan al-Minqari informed me, Muhammad ibn Ali Abu Ja’far narrated to us, my paternal uncle narrated to me, from my father: That he saw the Messenger of Allah, may Allah bless him and grant him peace, walking briskly (sa’i) between al-Safa and al-Marwah in the mas’a, with his garment uncovered, having reached up to his knees.