Sahih al-Bukhari, Hadith 2852 ⓘ
Narrated `Urwa Al-Bariqi: The Prophet said, "Good will remain (as a permanent quality) in the foreheads of horses (for Jihad) till the Day of Resurrection, for they bring about either a reward (in the Hereafter) or (war) booty (in this world)."
حَدَّثَنَا أَبُو نُعَيْمٍ، حَدَّثَنَا زَكَرِيَّاءُ، عَنْ عَامِرٍ، حَدَّثَنَا عُرْوَةُ الْبَارِقِيُّ، أَنَّ النَّبِيَّ صلى الله عليه وسلم قَالَ " الْخَيْلُ مَعْقُودٌ فِي نَوَاصِيهَا الْخَيْرُ إِلَى يَوْمِ الْقِيَامَةِ الأَجْرُ وَالْمَغْنَمُ " .
also referenced under: Book 56, Hadith 68 (In-Book) & Volume 4, Book 52, Hadith 104 (USC-MSA)