(14) باب مَا يُقَالُ لِلْمَرِيضِ وَمَا يُجِيبُ
Narrated `Abdullah:
I visited the Prophet (ﷺ) 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."
Reference: Sahih al-Bukhari 5661
In-book reference: Book 75, Hadith 22
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 7, Book 70, Hadith 565