Sahih al-Bukhari 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.
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا حَاتِمٌ، عَنْ يَزِيدَ بْنِ أَبِي عُبَيْدٍ، قَالَ سَمِعْتُ سَلَمَةَ بْنَ الأَكْوَعِ، يَقُولُ غَزَوْتُ مَعَ النَّبِيِّ صلى الله عليه وسلم سَبْعَ غَزَوَاتٍ، وَخَرَجْتُ فِيمَا يَبْعَثُ مِنَ الْبُعُوثِ تِسْعَ غَزَوَاتٍ، مَرَّةً عَلَيْنَا أَبُو بَكْرٍ، وَمَرَّةً عَلَيْنَا أُسَامَةُ‏.‏