One-fifth of Booty to the Cause of Allah (Khumus)
57/9. Chapter:
The war booty is for those who witness the battles
Sahih Bukhari
حَدَّثَنَا صَدَقَةُ، أَخْبَرَنَا عَبْدُ الرَّحْمَنِ، عَنْ مَالِكٍ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ أَبِيهِ، قَالَ قَالَ عُمَرُ ـ رضى الله عنه لَوْلاَ آخِرُ الْمُسْلِمِينَ مَا فَتَحْتُ قَرْيَةً إِلاَّ قَسَمْتُهَا بَيْنَ أَهْلِهَا كَمَا قَسَمَ النَّبِيُّ صلى الله عليه وسلم خَيْبَرَ.
Narrated Aslam: `Umar said, "Were it not for those Muslims who have not come to existence yet, I would have distributed (the land of) every town I conquer among the fighters as the Prophet (ﷺ) distributed the land of Khaibar."
Reference : Sahih al-Bukhari 3125In-book reference : Book 57, Hadith 34USC-MSA web (English) reference : Vol. 4, Book 53, Hadith 354