Hadith 517090
Chapter 50: The Evil Eye - كتاب العين
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " إِنَّ الْحُمَّى مِنْ فَيْحِ جَهَنَّمَ فَابْرُدُوهَا بِالْمَاءِ " .
Yahya related to me from Malik from Hisham ibn Urwa from his father that the Messenger of Allah, may Allah bless him and grant him peace, said, "Fever is from the vehemence of the heat of Jahannam, so cool it with water."
Reference Muwatta Malik 517090
USC-MSA web (English) reference : Book 50, Hadith 16