The description of the (Hell) Fire and the fact that it has already been created Sahih al-Bukhari 3259
Arabic hadith text
حَدَّثَنَا مُحَمَّدُ بْنُ يُوسُفَ، حَدَّثَنَا سُفْيَانُ، عَنِ الأَعْمَشِ، عَنْ ذَكْوَانَ، عَنْ أَبِي سَعِيدٍ، رضى الله عنه قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم "أَبْرِدُوا بِالصَّلاَةِ فَإِنَّ شِدَّةَ الْحَرِّ مِنْ فَيْحِ جَهَنَّمَ "
Translation
Narrated Abu Sa`d
The Prophet (ﷺ) said, "Delay the (Zuhr) Prayer till it gets cooler, for the severity of heat is from the increase in the heat of Hell (fire).