Malik related to me that Yahya ibn Said said, "I heard Abul-Hubab Said ibn Yasar say that he heard Abu Hurayra say that he heard the Messenger of Allah, may Allah bless him and grant him peace, say, I was ordered to a town which will eat up towns. They used to say, Yathrib, but it is Madina. It removes the bad people like the blacksmiths furnace removes impurities from the iron. "