'Aishah (May Allah be pleased with her) said:
The Prophet (ﷺ) said, "Fever comes from the vehement raging of Hell, so cool it with water."[Al-Bukhari and Muslim]. (DE)
App reference (DE): Book 19, Hadith 50 (DE)
Arabic/English book reference (DE): Book 19, Hadith 1857 (DE)