Sahih al-Bukhari 3261
Sahih al-Bukhari · Book 59: Beginning of Creation · The description of the (Hell) Fire and the fact that it has already been created
Narrated Abu Jamra Ad-Dabi:
حَدَّثَنِي عَبْدُ اللَّهِ بْنُ مُحَمَّدٍ ، حَدَّثَنَا أَبُو عَامِرٍ ، حَدَّثَنَا هَمَّامٌ ، عَنْ أَبِي جَمْرَةَ الضُّبَعِيِّ ، قَالَ كُنْتُ أُجَالِسُ ابْنَ عَبَّاسٍ بِمَكَّةَ، فَأَخَذَتْنِي الْحُمَّى، فَقَالَ أَبْرِدْهَا عَنْكَ بِمَاءِ زَمْزَمَ، فَإِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " الْحُمَّى مِنْ فَيْحِ جَهَنَّمَ فَأَبْرِدُوهَا بِالْمَاءِ ". أَوْ قَالَ " بِمَاءِ زَمْزَمَ ". شَكَّ هَمَّامٌ .
I used to sit with Ibn `Abbas in Mecca. Once I had a fever and he said (to me), "Cool your fever with Zamzam water, for Allah's Messenger (ﷺ) said: 'It, (the Fever) is from the heat of the (Hell) Fire; so, cool it with water (or Zamzam water).