This hadeeth comes under the following chapter: WHENEVER A BELIEVER FALLS SICK OR IS STRICKEN WITH GRIEF OR SOMETHING LIKE IT, THERE IS A REWARD FOR HIM EVEN IF IT IS PRICKING OF A THORN
Jabir b. Abdullah reported that Allaah's Messenger (sallAllaahu alayhi wa sallam) visited Umm Sa'ib or Umm Musayyib and said: Umm Sa'ib or Umm Musayyib. why is it that you are shivering? She said:" It is fever and may it not be blessed by Allaah, whereupon he (the Prophet) said: Don't curse fever for it expiates the sir of the posterity of Adam just as furnace removes the alloy of iron.