An Arabi pledged allegiance to the Prophet ﷺ upon Islam, then he was struck by a fever in Medina. He came to the Prophet ﷺ and said, "Muhammad, release me from my pledge."The Messenger of Allah ﷺ refused.Then he came again and said, "Release me from my pledge."He refused.Then he came once more and said, "Release me from my pledge."He refused, and the Arabi departed.The Messenger of Allah ﷺ then said, "Medina is like a bellows. It expels its impurities and purifies what is good in it."
أن أعرابيا بايع النبي ﷺ على الإسلام فأصاب الإعرابي وعك بالمدينة، فأتى النبي ﷺ فقال: يا محمد أقلني بيعتي، فأبى رسول الله ﷺ ثم جاءه فقال: أقلني بيعتي فأبى، ثم جاءه فقال: أقلني بيعتي فأبى فخرج الإعرابي فقال رسول الله ﷺ: إنما المدينة كالكير تنفي خبثها، وينصع طيبها.
Malik narrated it in Jami (4) from Muhammad bin Munkadir, from Jabir bin Abdullah, as mentioned. Bukhari narrated it in the Book of Judgments (7211), and Muslim in the Book of Hajj (489:1383), by way of Malik, with the same wording.His saying, "waak," means fever. His saying, "yansau," means it becomes clear.