I visited Allah's Messenger (ﷺ) while he was suffering from a high fever. I touched him with my hand and said, "O Allah's Messenger (ﷺ)! You have a high fever." Allah's Messenger (ﷺ) said, "Yes, I have as much fever as two men of you have." I said, "Is it because you will get a double reward?" Allah's Messenger (ﷺ) said, "Yes, no Muslim is afflicted with harm because of sickness or some other inconvenience, but that Allah will remove his sins for him as a tree sheds its leaves."
Sahih al-Bukhari Book 75, Hadith 20
← Previous Hadith I became seriously ill at Mecca and the Prophet (ﷺ) came to visit me. I said, "O Allah's Messenger (ﷺ)! I shall leave behind me a good fortune, but my heir is my only daughter; shall I bequeath two third of my property to be spent in charity and leave one third (for my heir)?" He said, "No." I said, "Shall I bequeath half and leave half?" He said, "No." I said, "Shall I bequeath one third and leave two thirds?" He said, "One third is alright, though even one third is too much." Then he placed his hand on his forehead and passed it over my face and `Abdomen and said, "O Allah! Cure Sa`d and complete his emigration." I feel as if I have been feeling the coldness of his hand on my liver ever since.

Sahih al-Bukhari Book 75, Hadith 19 Next Hadith → 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."

Sahih al-Bukhari Book 75, Hadith 21