It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) went to visit a sick Bedouin (a man of the desert) who had a fever. The Prophet (peace and blessings be upon him) said (to console him): "(This illness is) an expiation (of sins) and a means of purification." The Bedouin said (ungratefully): Not at all! Rather, it is a boiling fever that has befallen a very old man and will make him visit the graves (that is, will take him to his death). So the Prophet (peace and blessings be upon him) (on hearing this) got up and left him to his state.
Hadith Referenceمسند أبي يعلى الموصلي / مسند أنس بن مالك / 4232