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."
أَنَّ أَعْرَابِيًّا بَايَعَ رَسُولَ اللَّهِ ﷺ عَلَى الإِسْلاَمِ فَأَصَابَهُ وَعَكٌ بِالْمَدِينَةِ فَجَاءَ الأَعْرَابِيُّ إِلَى رَسُولِ اللَّهِ ﷺ فَقَالَ أَقِلْنِي بَيْعَتِي فَأَبَى رَسُولُ اللَّهِ ﷺ فَخَرَجَ الأَعْرَابِيُّ ثُمَّ جَاءَهُ فَقَالَ أَقِلْنِي بَيْعَتِي فَأَبَى فَخَرَجَ الأَعْرَابِيُّ فَقَالَ رَسُولُ اللَّهِ ﷺ إِنَّمَا الْمَدِينَةُ كَالْكِيرِ تَنْفِي خَبَثَهَا وَتُنَصِّعُ طَيِّبَهَا وَفِي الْبَابِ عَنْ أَبِي هُرَيْرَةَ هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ