"Messenger of Allah was on a journey and Bilal was with him. So he wanted to call for the prayer, but he (the Prophet) said: 'Let it get cooler.' Then he wanted to call for the prayer, so Messenger of Allah said: 'Let it get to the cooler time of Zuhr.'" He (i.e., Abu Dharr) said: "Until we saw the shadows of the hillocks, then he commanded that the Iqamah be called and then led the people in prayer. Messenger of Allah said: 'The severity of heat is from the raging of Hell, so wait until it becomes cooler for the (Zuhr) prayer.'"  

أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ فِي سَفَرٍ وَمَعَهُ بِلاَلٌ فَأَرَادَ بِلاَلٌ أَنْ يُقِيمَ فَقَالَ أَبْرِدْ ثُمَّ أَرَادَ أَنْ يُقِيمَ فَقَالَ رَسُولُ اللَّهِ ﷺ أَبْرِدْ فِي الظُّهْرِ قَالَ حَتَّى رَأَيْنَا فَىْءَ التُّلُولِ ثُمَّ أَقَامَ فَصَلَّى فَقَالَ رَسُولُ اللَّهِ ﷺ إِنَّ شِدَّةَ الْحَرِّ مِنْ فَيْحِ جَهَنَّمَ فَأَبْرِدُوا عَنِ الصَّلاَةِ  

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). (Using translation from Bukhārī 3259)  

عَنِ النَّبِيِّ ﷺ قَالَ إِنَّ شِدَّةَ الْحَرِّ مِنْ فَيْحِ جَهَنَّمَ فَأَبْرِدُوا بِالصَّلَاةِ  

[Machine] Abu Dharr heard the Messenger of Allah ﷺ saying: "We were with the Messenger of Allah ﷺ during a journey and the Muadhin intended to call the Adhan for Dhur prayer. The Prophet ﷺ told him, 'Cool down.' Then he intended to call the Adhan again and the Prophet ﷺ told him, 'Cool down' two or three times until we saw the shadow of a hillock. The Prophet ﷺ then said, 'Indeed, the intense heat is a portion of the Hellfire. So when it is extremely hot, cool yourselves with prayer.'"  

سَمِعَ أَبَا ذَرٍّ يَقُولُ كُنَّا مَعَ رَسُولِ اللَّهِ ﷺ فِي سَفَرٍ فَأَرَادَ الْمُؤَذِّنُ أَنْ يُؤَذِّنَ بِالظُّهْرِ فَقَالَ لَهُ النَّبِيُّ ﷺ «أَبْرِدْ» ثُمَّ أَرَادَ أَنْ يُؤَذِّنَ فَقَالَ لَهُ «أَبْرِدْ» مَرَّتَيْنِ أَوْ ثَلَاثًا حَتَّى رَأَيْنَا فَيْءَ التُّلُولِ وَقَالَ «إِنَّ شِدَّةَ الْحَرِّ مِنْ فَيْحِ جَهَنَّمَ فَإِذَا اشْتَدَّ الْحَرُّ فَأَبْرِدُوا بِالصَّلَاةِ»