Fever was mentioned in the presence of the Messenger of Allah ﷺ, and a man cursed it. The Prophet ﷺ said, "Do not curse it, for it removes sins just as fire removes the impurities of iron."
حدثنا أبو بكر بن أبي شيبة حدثنا وكيع عن موسى بن عبيدة عن علقمة بن مرثد عن حفص بن عبيد الله
ذكرت الحمى عند رسول الله ﷺ فسبها رجل فقال النبي ﷺ لا تسبها فإنها تنفي الذنوب كما تنفي النار خبث الحديد
No references are available.
[Sahih] It is found in Musannaf Ibn Abu Shayba, vol. 3, p. 231, though its chain is daif. Busiri graded it daif because of Musa bin Ubayda, see no. 251. It has corroborating narrations in Muslim, no. 2575, and elsewhere. See also Tanqih Ruwat, vol. 1, p. 304.