Sahih Adab al-Mufrad

It is narrated from Sayyiduna Jabir (may Allah be pleased with him) that the Messenger of Allah (peace and blessings of Allah be upon him) came to Umm Sa’ib, and she was shivering due to fever. He asked: “What has happened to you?” She said: “It is fever, may Allah disgrace it.” Upon this, the Prophet (peace and blessings of Allah be upon him) said: “Be quiet, do not speak ill of it. It removes the sins of a believer just as a furnace removes the rust from iron.”