Sahih Bukhari Volume 004, Book 052, Hadith Number 103.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 52. Fighting for the Cause of Allah (Jihaad)
Narated By Ursa bin Alga : The Prophet said, "Good will remain (as a permanent quality) in the foreheads of horses till the Day of Resurrection." And narrated Anas bin Malik: Allah's Apostle said, "There is a blessing in the fore-heads of horses."