Sahih al-Bukhari
Sahih al-Bukhari 7209
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ، عَنْ مَالِكٍ، عَنْ مُحَمَّدِ بْنِ الْمُنْكَدِرِ، عَنْ جَابِرِ بْنِ عَبْدِ اللَّهِ ـ رضى الله عنهما ـ أَنَّ أَعْرَابِيًّا بَايَعَ رَسُولَ اللَّهِ صلى الله عليه وسلم عَلَى الإِسْلاَمِ، فَأَصَابَهُ وَعْكٌ فَقَالَ أَقِلْنِي بَيْعَتِي. فَأَبَى، ثُمَّ جَاءَهُ فَقَالَ أَقِلْنِي بَيْعَتِي. فَأَبَى، فَخَرَجَ. فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " الْمَدِينَةُ كَالْكِيرِ، تَنْفِي خَبَثَهَا، وَيَنْصَعُ طِيبُهَا ".
Jābir ibn ʿAbd Allāh reported that a Bedouin pledged allegiance to the Messenger of God to accept Islam. He was afflicted by a fever and said, “Release me from my pledge.” The Prophet refused. He came again and said, “Release me from my pledge,” but the Prophet refused. So the man left. The Messenger of God said, “Medina is like a blacksmith’s bellows: it removes its impurities and makes its good pure.”
Translation notes
The source compares Medina to a blacksmith’s bellows, which expels impurities and purifies what is good. The Bedouin asks twice to be released from his pledge, and both requests are refused.