Sayyiduna Jabir bin Abdullah (may Allah be pleased with him) narrates: A Bedouin came to Madinah Munawwarah, and he pledged allegiance of migration at the blessed hand of the Prophet Muhammad (peace and blessings be upon him). He developed a fever, so he came to the Prophet (peace and blessings be upon him) and said: "O Messenger of Allah! Please return my pledge to me." The Prophet (peace and blessings be upon him) said: "No!" Then his fever intensified, so he again came to the Prophet (peace and blessings be upon him) and said: "O Messenger of Allah! Please return my pledge to me." The Prophet (peace and blessings be upon him) said: "No!" Then his fever became even more severe. He came to the Prophet (peace and blessings be upon him) and said: "O Messenger of Allah! Please return my pledge to me." The Prophet (peace and blessings be upon him) said: "No!" Then his fever became extremely severe, so he left Madinah Munawwarah out of fear. The Prophet (peace and blessings be upon him) said: "The example of Madinah is like that of a furnace, which removes impurities and refines the pure."