Volume 7, Book 70, Number 566:
Narrated Ibn ‘Abbas:
Allah’s Apostle entered upon sick man to pay him a visit, and said to him, “Don’t worry, Allah will –
ing, (your sickness will be) an expiation for your sins.” The man said, “No, it is but a fever that is boil –
ing within an old man and will send him to his grave.” On that, the Prophet said, “Then yes, it is so.”