Musannaf Ibn Abi Shayba 37:518

Ghundar narrated to us, from Shu'bah, from al-Hakam, who said: I heard Abu Sadiq narrating from al-Rabi' ibn Najidh, from Ibn Mas'ud, who said: "A people will come to you from the direction of the east, broad-faced, small-eyed, as if their eyes were pierced into rock, as if their faces were hammered shields, until they tether their horses by the bank of the Euphrates."