Musannaf Ibn Abi Shayba 27:54

Ubayd Allah ibn Musa narrated to us, from Isra'il, from Asim, from Zirr, from Hudhayfah, who said: The Messenger of Allah (may Allah bless him and grant him peace) passed by me and said: "I am Muhammad, and Ahmad, and al-Muqaffa (the Successor), and al-Hashir (the Gatherer)."