Sunan At-Tirmidhi

Narrated Jabir:that a Bedouin gave the pledge to the Messenger of Allah (ﷺ) for Islam, then he was afflicted by the sickness in Al-Madinah. So the Bedouin went to the Messenger of Allah (ﷺ) and said: ""Take back my pledge."" But the Messenger of Allah (ﷺ) refused. Then the Bedouin left and came back and said: ""Take back my pledge,"" and he refused. Then the Messenger of Allah (ﷺ) said: ""Al-Madinah is but like bellows, it expels its filth and purifies its good