Narrated `Abdullah bin Mas`ud: I visited Allah's Apostle while he was suffering from a high fever. I touched him with my hand and said,   O Allah's Apostle! You have a high fever.   Allah's Apostle 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 Apostle 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.