Yahya related to me from Malik from Muhammad ibn al-Munkadir from Jabir ibn Abdullah that a Bedouin took an oath of allegiance in Islam with the Messenger of Allah (ﷺ). A fever befell the Bedouin at Madina. He came to the Messenger of Allah, and said, "Messenger of Allah, release me from my pledge." The Messenger of Allah (ﷺ) refused. Then he came to him again and said, "Release me from my pledge." The Messenger of Allah may Allah bless him and grant him peace, refused. Then he came again and said, "Release me from my pledge." He refused. Then he came again and said, "Release me from my pledge." He refused. The Bedouin left and the Messenger of Allah (ﷺ) said, "Madina is like the blacksmith's furnace. It removes the impurities and purifies the good."