Sahih Muslim
The Book on Salutations and Greetings (Kitab As-Salam)
Book Number: 026 / Hadith Number: 5485
Rafi' b. Khadij reported: I heard Allah's Messenger (may peace be upon him) as saying: The fever is due to the intense heat of Hell, so cool it down in your (bodies) with water. Aba Bakr has made no mention of the word" from you" ('ankum), but he said that Rafi' b. Khadij had informed him of it.