Abdullah bin Masud reported,

I came to the Prophet ﷺ during his illness while he was suffering from a severe fever, and I said, "You are suffering from a very severe fever."I added, "That is because you have a double reward."He replied, "Indeed. No Muslim is afflicted by any harm without Allah causing his sins to fall away from him as the leaves fall from a tree."

Bukhari 5647

Sahih

حدثنا محمد بن يوسف حدثنا سفيان عن الأعمش عن إبراهيم التيمي عن الحارث بن سويد

عن عبد الله رضي الله عنه

أتيت النبي ﷺ في مرضه وهو يوعك وعكا شديدا وقلت إنك لتوعك وعكا شديدا قلت إن ذاك بأن لك أجرين قال أجل ما من مسلم يصيبه أذى إلا حات الله عنه خطاياه كما تحات ورق الشجر

البخاري 5647صحيح
Contents
Reference
Commentary
Ayat
Collection
Sahih Bukhari
Book
Sick
Chapter
Severity of illness
Numbering
Darussalam 5647
Bukhari 5647