English Translation
Narrated 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."
This hadith is from Sahih al-Bukhari, the most rigorously authenticated collection in Islamic scholarship. No editorial opinion is added.