Allah will remove his sins as the leaves of a tree fall down

Narrated 'Abdullah (radiyallahu 'anhu): I visited the Prophet (sallallahu 'alayhi wasallam) during his ailments and he was suffering from a high fever. I said, "You have a high fever. Is it because you will have a double reward for it?" He (sallallahu 'alayhi wasallam) said, "Yes, for no Muslim is afflicted with any harm but that Allah will remove his sins as the leaves of a tree fall down." Bukhari : Book 7 : Volume 70 : Hadith 550