English Translation
Narrated Ibn Abbas: The Prophet went to visit a sick bedouin. Whenever the Prophet 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 said, "Then, yes, it is so."
This hadith is from Sahih al-Bukhari, the most rigorously authenticated collection in Islamic scholarship. No editorial opinion is added.