Narrated `Abdullah: I visited the Prophet during his illness and touched him while he was having a fever. I said to him, "You have a high fever; is it because you will get a double reward?" He said, "Yes. No Muslim is afflicted with any harm, but that his sins will be annulled as the leave of a tree fall down."
Hadith Referenceصحيح البخاري / كتاب المرضى / 5661
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة
Narrated Ibn `Abbas: Allah's Apostle entered upon sick man to pay him a visit, and said to him, "Don't worry, Allah willing, (your sickness will be) an expiation for your sins." The man said, "No, it is but a fever that is boiling within an old man and will send him to his grave." On that, the Prophet said, "Then yes, it is so."
Hadith Referenceصحيح البخاري / كتاب المرضى / 5662
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة