Sahih al-Bukhari 3119
Book 57: One-fifth of Booty to the Cause of Allah (Khumus) · Narrated by `Urwa-al-Bariqi
Arabic
حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا خَالِدٌ، حَدَّثَنَا حُصَيْنٌ، عَنْ عَامِرٍ، عَنْ عُرْوَةَ الْبَارِقِيِّ ـ رضى الله عنه ـ عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " الْخَيْلُ مَعْقُودٌ فِي نَوَاصِيهَا الْخَيْرُ الأَجْرُ وَالْمَغْنَمُ إِلَى يَوْمِ الْقِيَامَةِ ".
English translation
Narrated `Urwa-al-Bariqi:The Prophet (ﷺ) said, "Horses are always the source of good, namely, rewards (in the Hereafter) and booty, till the Day of Resurrection
Reference: Sahih al-Bukhari 3119, Book of One-fifth of Booty to the Cause of Allah (Khumus). English translation by Dr. Muhammad Muhsin Khan.