(10) باب عِيَادَةِ الأَعْرَابِ
Narrated Ibn `Abbas:
The Prophet (ﷺ) went to visit a sick bedouin. Whenever the Prophet (ﷺ) went to a patient, he used to say to him, "Don't worry, if Allah will, it will be expiation (for your sins):" The bedouin said, "You say expiation? No, it is but a fever that is boiling or harassing an old man and will lead him to his grave without his will." The Prophet (ﷺ) said, "Then, yes, it is so."
Reference: Sahih al-Bukhari 5656
In-book reference: Book 75, Hadith 17
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 7, Book 70, Hadith 560