Musnad Ahmad 4177

It was narrated that ‘Abdullah said: I entered upon the Messenger of Allah (ﷺ) and he was running a fever, I said: O Messenger of Allah, you are running a high fever. The Messenger of Allah (ﷺ) said: "Yes, I am running a fever like two of you.” I said: Then you will have two rewards. The Messenger of Allah (ﷺ) said: “Yes." Then he said: “There is no Muslim who is afflicted with and harm, a thorn or anything greater than that, but Allah will erase thereby his bad deeds just as trees shed their leaves."