عَنْ عَائِشَةَ رَضِيَ اللَّهُ عَنْهَا عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ إِنَّ الْحُمَّى أَوْ شِدَّةَ الْحُمَّى مِنْ فَيْحِ جَهَنَّمَ فَأَبْرِدُوهَا بِالْمَاءِ
Lady Aisha (may Allah be pleased with her) narrates that the Noble Prophet (peace and blessings be upon him) said: "The severity of fever is from the steam of Hell, so cool it with water."