Sahih Bukhari Volume 4, Book 52, Hadith Number 180.

Narated By Abu Huraira : The Prophet said, “The Hour will not be established till you fight with people wearing shoes made of hair. And the Hour will not be established till you fight with people whose faces look like shields coated with leather. ” (Abu Huraira added, “They will be) small-eyed, flat nosed, and their faces will look like shields coated with leather.”)