وَحَدَّثَنِي مَالِكٌ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏"‏ الْحُمَّى مِنْ فَيْحِ جَهَنَّمَ فَأَطْفِئُوهَا بِالْمَاءِ ‏"‏ ‏.‏

Malik related to me from Nafi from IbnUmar that the Messenger of Allah, may Allah bless him and grant himpeace, said, "Fever is from the vehemence of the heat of Jahannam, soput it out with water." Translation Not Available

Book Ref: Muwatta Imam Malik Book 50 Hadith 1730
Web Ref:  Muwatta Imam Malik Book 50 Hadith 16