It is narrated from Hazrat Anas (may Allah be pleased with him) that once the Prophet (peace and blessings be upon him) went to visit a Bedouin who had a fever. The Prophet (peace be upon him) said, "If Allah wills, this fever will be an expiation for your sins and a means of purification for you." The Bedouin replied, "No, this is a raging fever that has come upon an old man and will not leave him until it shows him his grave." Upon hearing this, the Prophet (peace be upon him) left him and stood up.