Sayyiduna Jabir (may Allah be pleased with him) narrates: A Bedouin accepted Islam at the blessed hand of the Prophet (peace and blessings be upon him). That Bedouin developed a fever in Madinah. He (left Madinah and) went away, so the Prophet (peace and blessings be upon him) said: "Indeed, Madinah is like a furnace; it removes impurities and refines goodness."