كتاب المغازى
64  
Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi)
(45)
Chapter: The dispatch of Usama bin Zaid to Al-Huraqat
(45)
باب بَعْثُ النَّبِيِّ صلى الله عليه وسلم أُسَامَةَ بْنَ زَيْدٍ إِلَى الْحُرَقَاتِ مِنْ جُهَيْنَةَ
Sahih al-Bukhari 4271
Narrated Salama (in another narration):
I fought seven Ghazwat (i.e. battles) along with the Prophet (ﷺ) and also fought in nine battles, fought by armies sent by the Prophet (ﷺ) . Once Abu Bakr was our commander and another time, Usama was (our commander).
وَقَالَ عُمَرُ بْنُ حَفْصِ بْنِ غِيَاثٍ حَدَّثَنَا أَبِي، عَنْ يَزِيدَ بْنِ أَبِي عُبَيْدٍ، قَالَ سَمِعْتُ سَلَمَةَ، يَقُولُ غَزَوْتُ مَعَ النَّبِيِّ صلى الله عليه وسلم سَبْعَ غَزَوَاتٍ، وَخَرَجْتُ فِيمَا يَبْعَثُ مِنَ الْبَعْثِ تِسْعَ غَزَوَاتٍ، عَلَيْنَا مَرَّةً أَبُو بَكْرٍ، وَمَرَّةً أُسَامَةُ‏.‏
Reference : Sahih al-Bukhari 4271
In-book reference : Book 64, Hadith 305
USC-MSA web (English) reference : Vol. 5, Book 59, Hadith 569
  (deprecated numbering scheme)