Sahih Bukhari Volume 009, Book 093, Hadith Number 562.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 93. Oneness, Uniqueness of Allah (Tawheed)
Narrated By Ibn 'Abbas : Allah's Apostle entered upon a sick bedouin in whom he went to visit and said to him, "Don't worry, Tahur (i.e., your illness will be a means of cleansing of your sins), if Allah Will." The bedouin said, "Tahur! No, but it is a fever that is burning in the body of an old man and it will make him visit his grave." The Prophet said, "Then it is so."