A bedouin Arab pledged allegiance to the Messenger of Allah ﷺ, then the Arabi 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 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.So the Arabi left, and the Messenger of Allah ﷺ said, "Medina is like a blacksmith's bellows. It expels its impurities and its goodness shines forth."
أن أعرابيا بايع رسول الله ﷺ، فأصاب الأعرابي وعك بالمدينة، فأتى النبي ﷺ فقال: يا محمد! أقلني بيعتي، فأبى رسول الله ثم جاءه فقال: أقلني بيعتي، فأبى، ثم جاءه فقال: أقلني بيعتي فأبى، فخرج الأعرابي فقال رسول الله ﷺ: إنما المدينة كالكير تنفي خبثها، وينصع طيبها.
Malik narrated it in al-Jami (4) from Muhammad bin Munkadir, from Jabir bin Abdullah, and he mentioned it.Bukhari narrated it in the Book of Rulings (7211), and Muslim in the Book of Hajj (383:489), both of them through Malik, in like manner.