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 booty (in this world."
— Sahih Bukhari, Volume 4, Book 52: Fighting for the Cause of Allah (Jihaad), Hadith #104