Musnad Abu Ya'la al-Mawsili 160:161

A Bedouin came to the Prophet, may Allah bless him and grant him peace, and his health and vigor impressed him. The Messenger of Allah, may Allah bless him and grant him peace, said to him, "When did you last feel *Umm Mildam*?" The Bedouin said, "And what is *Umm Mildam*?" He said, "The fever." He said, "And what is the fever?" The Messenger of Allah, may Allah bless him and grant him peace, said to him, "A heat that exists between the skin and the bone." The Bedouin said, "I have no experience with that." He said to him, "Then when did you last feel a headache?" He said, "And what is a headache?" He said, "A throbbing that occurs in the temples and the head." He said, "I have no experience with that." When the Bedouin turned away, the Messenger of Allah, may Allah bless him and grant him peace, said, "Whoever is pleased to look at a man from the people of the Fire, let him look at him," meaning the Bedouin.