Sahih al-Bukhari, Hadith 2792 ⓘ
Narrated Anas bin Malik: The Prophet said, "A single endeavor (of fighting) in Allah's Cause in the forenoon or in the afternoon is better than the world and whatever is in it."
حَدَّثَنَا مُعَلَّى بْنُ أَسَدٍ، حَدَّثَنَا وُهَيْبٌ، حَدَّثَنَا حُمَيْدٌ، عَنْ أَنَسِ بْنِ مَالِكٍ ـ رضى الله عنه ـ عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " لَغَدْوَةٌ فِي سَبِيلِ اللَّهِ أَوْ رَوْحَةٌ خَيْرٌ مِنَ الدُّنْيَا وَمَا فِيهَا " .
also referenced under: Book 56, Hadith 10 (In-Book) & Volume 4, Book 52, Hadith 50 (USC-MSA)