Sahih al-Bukhari 123
صحيح البخاري#123SahihNarrated Abu Musa:A man came to the Prophet (ﷺ) and asked, "O Allah's Messenger (ﷺ)! What kind of fighting is in Allah's cause? (I ask this), for some of us fight because of being enraged and angry and some for the sake of his pride and haughtiness." The Prophet (ﷺ) raised his head (as the questioner was standing) and said, "He who fights so that Allah's Word (Islam) should be superior, then he fights in Allah's cause
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 3:65