Musnad Abu Ya'la al-Mawsili 41:22

Abu Khaythama and Ya'qub ibn Ibrahim narrated to us, they said: Hushaym narrated to us, Husayn informed us, from Hilal ibn Yasaf, from Abdullah ibn Zalim al-Mazini, from Sa'id ibn Zayd, who said: I bear witness regarding the nine that they are in Paradise, and if I were to bear witness regarding the tenth, I would not be sinful. It was said: How is that? He said: We were with the Messenger of Allah, peace and blessings of Allah be upon him, at Hira, and he said: "Be still, Hira, for there is upon you none but a Prophet, or a Siddiq (truthful one), or a martyr." It was said: Who are they? He said: The Messenger of Allah, peace and blessings of Allah be upon him, Abu Bakr, Umar, Ali, Uthman, Talha, al-Zubayr, Sa'd, and Ibn Awf. It was said: Then who is the tenth? He said: I—meaning himself.