Sahih Muslim — The Book of Greetings — Hadith No: 5757
وَحَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا عَبْدَةُ بْنُ سُلَيْمَانَ، عَنْ هِشَامٍ، عَنْ فَاطِمَةَ، عَنْ أَسْمَاءَ، أَنَّهَا كَانَتْ تُؤْتَى بِالْمَرْأَةِ الْمَوْعُوكَةِ فَتَدْعُو بِالْمَاءِ فَتَصُبُّهُ فِي جَيْبِهَا وَتَقُولُ إِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " ابْرُدُوهَا بِالْمَاءِ " . وَقَالَ " إِنَّهَا مِنْ فَيْحِ جَهَنَّمَ " .
Translation
Asma' reported that a woman running high fever was brought to her. She asked water to be brought and then sprinkled it in the opening of a shirt at the uppermost part of the chest and said that Allah's Messenger (ﷺ) had said:Cool (the fever) with water. for it is because of the vehemence of the beat of Hell