Sahih Bukhari
Fighting for the Cause of Allah (Jihaad)
Volume: 004 / Book Number: 052 / Hadith Number: 179
Narrated Abu Huraira:
Allah's Apostle said, "The Hour will not be established until you fight with the Turks; people with small eyes, red faces, and flat noses. Their faces will look like shields coated with leather. The Hour will not be established till you fight with people whose shoes are made of hair."