Musnad Abu Ya'la al-Mawsili 6:106

Zuhayr narrated to us, Muhammad ibn Khazim narrated to us, Isma'il ibn Abi Khalid narrated to us, from Qays ibn Abi Hazim: That Sa'd ibn Abi Waqqas stood up during the two rak'ahs, so they glorified Allah (said "SubhanAllah") to him. He completed it, then said: "Did you think I would sit? I only did as I saw the Messenger of Allah, may Allah bless him and grant him peace, do."