Sahih al-Bukhari 629
Narrated Abu Dhar:
We were in the company of the Prophet (ﷺ) on a journey and the Mu'adh-dhin wanted to pronounce the 
Adhan for the (Zuhr) prayer. The Prophet (ﷺ) said to him, "Let it become cooler." Then he again wanted 
to pronounce the Adhan but the Prophet; said to him, "Let it become cooler." The Mu'adh-dhin again 
wanted to pronounce the Adhan for the prayer but the Prophet (ﷺ) said, "Let it become cooler," till the 
shadows of the hillocks become equal to their sizes. The Prophet (ﷺ) added, "The severity of the heat is 
from the raging of Hell."
حَدَّثَنَا مُسْلِمُ بْنُ إِبْرَاهِيمَ، قَالَ حَدَّثَنَا شُعْبَةُ، عَنِ الْمُهَاجِرِ أَبِي الْحَسَنِ، عَنْ زَيْدِ بْنِ وَهْبٍ، عَنْ أَبِي ذَرٍّ، قَالَ كُنَّا مَعَ النَّبِيِّ صلى الله عليه وسلم فِي سَفَرٍ فَأَرَادَ الْمُؤَذِّنُ أَنْ يُؤَذِّنَ فَقَالَ لَهُ ‏"‏ أَبْرِدْ ‏"‏‏.‏ ثُمَّ أَرَادَ أَنْ يُؤَذِّنَ فَقَالَ لَهُ ‏"‏ أَبْرِدْ ‏"‏‏.‏ ثُمَّ أَرَادَ أَنْ يُؤَذِّنَ‏.‏ فَقَالَ لَهُ ‏"‏ أَبْرِدْ ‏"‏‏.‏ حَتَّى سَاوَى الظِّلُّ التُّلُولَ فَقَالَ النَّبِيُّ صلى الله عليه وسلم ‏{‏إِنَّ شِدَّةَ الْحَرِّ مِنْ فَيْحِ جَهَنَّمَ‏}‏