Sahih Bukhari
Fighting for the Cause of Allah (Jihaad)
Volume: 004 / Book Number: 052 / Hadith Number: 103
Narrated 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."