The Book of Jihad and Expedition (Kitab Al-Jihad wa'l-Siyar)
Muslim :: Book 19 : Hadith 4469
It has been narrated on the authority of Salama who said: I joined seven military expeditions led by the Messenger of Allah himself (may peace be upon him), and nine expeditions which he sent out once under Abu Bakr and once under Usama b. Zaid.