Musnad Abu Ya'la al-Mawsili 4:37

Abu Hisham al-Rifa'i narrated to us, Yahya ibn Yaman narrated to us, a sheikh from Banu Zuhrah narrated to us, from al-Harith ibn 'Abd al-Rahman, from Talhah ibn 'Ubayd Allah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "For every prophet there is a companion, and my companion is 'Uthman."