(47) باب مَنْ بَايَعَ ثُمَّ اسْتَقَالَ الْبَيْعَةَ
Narrated Jabir bin `Abdullah:
A bedouin gave the Pledge of allegiance to Allah's Messenger (ﷺ) for Islam. Then the bedouin got fever at Medina, came to Allah's Messenger (ﷺ) and said, "O Allah's Messenger (ﷺ)! Cancel my Pledge," But Allah's Apostle refused. Then he came to him (again) and said, "O Allah's Messenger (ﷺ)! Cancel my Pledge." But the Prophet (ﷺ) refused Then he came to him (again) and said, "O Allah's Messenger (ﷺ)! Cancel my Pledge." But the Prophet (ﷺ) refused. The bedouin finally went out (of Medina) whereupon Allah's Messenger (ﷺ) said, "Medina is like a pair of bellows (furnace): It expels its impurities and brightens and clears its good.
Reference: Sahih al-Bukhari 7211
In-book reference: Book 93, Hadith 71
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 9, Book 89, Hadith 318