(15) باب مَنْ قَاتَلَ لِتَكُونَ كَلِمَةُ اللَّهِ هِيَ الْعُلْيَا
Narrated Abu Musa:
A man came to the Prophet (ﷺ) and asked, "A man fights for war booty; another fights for fame and a third fights for showing off; which of them fights in Allah's Cause?" The Prophet (ﷺ) said, "He who fights that Allah's Word (i.e. Islam) should be superior, fights in Allah's Cause."
Reference: Sahih al-Bukhari 2810
In-book reference: Book 56, Hadith 26
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 4, Book 52, Hadith 65