ʿAbdullah bin ʿUmar said, "The Prophet ﷺ said, 'Fever is from the heat of Hell, so put it out (cool it) with water.' " Nafiʿ added: ʿAbdullah used to say, "O Allah! Relieve us from the punishment," (when he suffered from fever).  

عَنِ النَّبِيِّ ﷺ قَالَ الْحُمَّى مِنْ فَيْحِ جَهَنَّمَ فَأَطْفِئُوهَا بِالْمَاءِ قَالَ نَافِعٌ وَكَانَ عَبْدُ اللَّهِ يَقُولُ اكْشِفْ عَنَّا الرِّجْزَ  

Whenever a lady suffering from fever was brought to Asma' bint Abu Bakr, she used to invoke Allah for her and then sprinkle some water on her body, at the chest and say, "Messenger of Allah ﷺ used to order us to abate fever with water."  

أَنَّ أَسْمَاءَ بِنْتَ أَبِي بَكْرٍ ؓ كَانَتْ إِذَا أُتِيَتْ بِالْمَرْأَةِ قَدْ حُمَّتْ تَدْعُو لَهَا أَخَذَتِ الْمَاءَ فَصَبَّتْهُ بَيْنَهَا وَبَيْنَ جَيْبِهَا قَالَتْ وَكَانَ رَسُولُ اللَّهِ ﷺ يَأْمُرُنَا أَنْ نَبْرُدَهَا بِالْمَاءِ  

The Prophet ﷺ said, "Fever is from the heat of Hell, so abate fever with water."  

عَنِ النَّبِيِّ ﷺ قَالَ الْحُمَّى مِنْ فَيْحِ جَهَنَّمَ فَابْرُدُوهَا بِالْمَاءِ  

I heard Messenger of Allah ﷺ saying, "Fever is from the heat of Hell, so abate fever with water."  

سَمِعْتُ النَّبِيَّ ﷺ يَقُولُ الْحُمَّى مِنْ فَوْحِ جَهَنَّمَ فَابْرُدُوهَا بِالْمَاءِ