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.