Sahih al-Bukhari 3263
Book 59: Beginning of Creation · Narrated by Aisha
Arabic
حَدَّثَنَا مَالِكُ بْنُ إِسْمَاعِيلَ، حَدَّثَنَا زُهَيْرٌ، حَدَّثَنَا هِشَامٌ، عَنْ عُرْوَةَ، عَنْ عَائِشَةَ ـ رضى الله عنها ـ عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " الْحُمَّى مِنْ فَيْحِ جَهَنَّمَ، فَأَبْرِدُوهَا بِالْمَاءِ ".
English translation
Narrated Aisha:The Prophet (ﷺ) said, "Fever is from the heat of the (Hell) Fire, so cool it with water
Reference: Sahih al-Bukhari 3263, Book of Beginning of Creation. English translation by Dr. Muhammad Muhsin Khan.