Jabir ibn Abdullah radiallahu anhu reported that Allah's Messenger peace be upon him visited Umm Sa'ib radiallahu anho and said:

'Umm Sa'ib, why is it that you are shivering? She said:" It is fever and may it not be blessed by Allah, whereupon he said: Don't curse fever for it expiates the sin of the children of Adam just as furnace removes the alloy of iron.'

A believer should not insult the disease. Here we must pay special attention to the Prophet's behaviour (peace be upon him). Not only did he say to her, "Do not curse her fever," but he also told her the wisdom of the illness:

'Don't curse fever for it expiates the sin of the children of Adam just as furnace removes the alloy of iron.'

Is it possible for a Muslim to curse what clear his own sins? On the contrary, he should be grateful.