From Sahih Bukhari (Hadith 4270):
Narrated Salama bin Al-Akwa`:I fought in seven Ghazwat (i.e. battles) along with the Prophet (ﷺ) and fought in nine battles, fought by armies dispatched by the Prophet. Once Abu Bakr was our commander and at another time, Usama was our commander
Reference: Bukhari 4270