A bedouin gave the Pledge of allegiance to Allah's Messenger (ﷺ) for Islam and the bedouin got a fever where upon he said to the Prophet (ﷺ) "Cancel my Pledge." But the Prophet (ﷺ) refused. He came to him (again) saying, "Cancel my Pledge.' But the Prophet (ﷺ) refused. Then (the bedouin) left (Medina). Allah's Apostle said: "Medina is like a pair of bellows (furnace): It expels its impurities and brightens and clears its good."
Sahih al-Bukhari Book 93, Hadith 69
← Previous Hadith We gave the oath of allegiance to the Prophet (ﷺ) under the tree. He said to me, "O Salama! Will you not give the oath of allegiance?" I replied, "O Allah's Messenger (ﷺ)! I have already given the oath of allegiance for the first time." He said, (Give it again) for the second time.

Sahih al-Bukhari Book 93, Hadith 68 Next Hadith → who was born during the lifetime of the Prophet (ﷺ) that his mother, Zainab bint Humaid had taken him to Allah's Messenger (ﷺ) and said, "O Allah's Messenger (ﷺ)! Take his Pledge of allegiance (for Islam)." The Prophet (ﷺ) said, "He (`Abdullah bin Hisham) is a little child," and passed his hand over his head and invoked Allah for him. `Abdullah bin Hisham used to slaughter one sheep as a sacrifice on behalf of all of his family.

Sahih al-Bukhari Book 93, Hadith 70