Suffering sickness/distress removes sins

Narrated 'Abdullah:

I visited Allah's Apostle while he was suffering from a high fever. I said, "O Allah's Apostle! You have a high fever." He said, "Yes, I have as much fever as two men of you." I said, "Is it because you will have a double reward?" He said, "Yes, it is so. No Muslim is afflicted with any harm, even if it were the prick of a thorn, but that Allah expiates his sins because of that, as a tree sheds its leaves."
[Volume 7, Book 70, Number 551]

Narrated Hazrat Aisha (Radhiyallahu-Anha):

"I never saw anybody suffering so much from sickness as Allah's Apostle."
[Volume 7, Book 70, Number 549]