Muslim

Hadith Commentary:
1.
There is a difference of opinion regarding the number of military expeditions (ghazawat) of the Messenger of Allah (sallallahu alayhi wa sallam).
The reliable view is that the Messenger of Allah (sallallahu alayhi wa sallam) fought eighteen battles.
In eight of them, there was killing and bloodshed.
These include Badr, Uhud, Ahzab, Fari‘ah, Bi’r Ma‘unah, the expedition against Banu Mustaliq, Khaybar, and the eighth is the expedition of the conquest of Makkah.
The battles of Hunayn and Ta’if are also included in this.
It should be noted that Abu Ishaq had great interest regarding the expeditions (ghazawat) of the Messenger of Allah (sallallahu alayhi wa sallam) and their number.
This is why he asked Zayd ibn Arqam, al-Bara’ ibn ‘Azib (radi Allahu anhuma), and other noble Companions (radi Allahu anhum ajma‘in) about this matter.
(Fath al-Bari: 8/192)
Imam al-Bukhari (rahimahullah) concluded the Book of Expeditions (Kitab al-Maghazi) with this chapter so that there would be uniformity between the beginning and the end.
And Allah knows best; His knowledge is most complete.

Hadith Commentary: Benefits and Issues: The Prophet sallallahu alayhi wa sallam participated in battle in the expeditions (ghazawat) of Badr, Uhud, Muraysi', Khandaq, Qurayzah, Khaybar, Makkah, Hunayn, and Ta'if.

Hazrat Buraydah radi Allahu anhu counted Khandaq and Qurayzah, or Hunayn and Ta'if, as one, and thus mentioned the number as eight. In this way, by counting nearby expeditions as one, the total number of expeditions (ghazawat) is reduced.