Abu Dawud
The Promised Deliverer
Book Number: 031 / Hadith Number: 4272
Narated By Abu Sa'id al-Khudri : The Prophet (pbuh) said: The Mahdi will be of my stock, and will have a broad forehead a prominent nose. He will fill the earth will equity and justice as it was filled with oppression and tyranny, and he will rule for seven years.