Silsilat al-Ahadith al-Sahihah

Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates that I heard the Messenger of Allah (peace and blessings be upon him) say: "I have been commanded to go to a town whose (inhabitants) will prevail over other towns. People call it Yathrib, but it is Madinah, which removes evils from people just as a furnace removes impurities from iron." In another narration, it is stated: "A time will come upon people when a man will call his paternal cousin or a relative, saying: (Leave Madinah and) come towards prosperity, come towards comfort. But residing in Madinah will be better for them. If only they knew this reality. By the One in Whose hand is my soul! Whenever a person leaves Madinah out of dislike for it, Allah will bring someone better than him in his place. Be aware! Madinah is like a furnace that expels wicked people. The Hour will not be established until Madinah expels the evil ones (by exiling them) in the same way that a furnace removes the impurities of iron."