The Messenger of Allah ﷺ visited Umm Saaib, or Umm Musayyab, and asked, "What is wrong with you, Umm Saaib, or Umm Musayyab, that you are shivering?"She replied, "It is the fever, may Allah not bless it!"He said, "Do not curse the fever, for it removes the sins of the children of Adam just as the bellows removes impurities from iron."
أن رسول الله ﷺ دخل على أم السائب، أو أم المسيب، فقال: ما لك يا أم السائب، أو أم المسيب تزفزفين؟ قالت: الحمى لا بارك الله فيها! فقال: لا تسبي الحمى؛ فإنها تذهب خطايا بني آدم كما يذهب الكير خبث الحديد.
Muslim reported it in "Virtue and Kinship" (2575), from Ubaydullah bin Qawariri, who said, Yazid bin Zuray narrated to us, who said, Hajjaj Sawwaf narrated to us, who said, Abu Zubayr narrated to me, who said, Jabir bin Abdullah narrated to us, and he mentioned it.