Sahih Muslim 616
Sahih Muslim · Book 5: The Book of Mosques and Places of Prayer · The recommendation to delay Zuhr (until it has cooled down) in severe heat for one who finds it too hot in route to join the congregation
Abu Dharr reported:
حَدَّثَنِي مُحَمَّدُ بْنُ الْمُثَنَّى ، حَدَّثَنَا مُحَمَّدُ بْنُ جَعْفَرٍ ، حَدَّثَنَا شُعْبَةُ ، قَالَ سَمِعْتُ مُهَاجِرًا أَبَا الْحَسَنِ ، يُحَدِّثُ أَنَّهُ سَمِعَ زَيْدَ بْنَ وَهْبٍ ، يُحَدِّثُ عَنْ أَبِي ذَرٍّ ، قَالَ أَذَّنَ مُؤَذِّنُ رَسُولِ اللَّهِ صلى الله عليه وسلم بِالظُّهْرِ فَقَالَ النَّبِيُّ صلى الله عليه وسلم " أَبْرِدْ أَبْرِدْ " . أَوْ قَالَ " انْتَظِرِ انْتَظِرْ " . وَقَالَ " إِنَّ شِدَّةَ الْحَرِّ مِنْ فَيْحِ جَهَنَّمَ فَإِذَا اشْتَدَّ الْحَرُّ فَأَبْرِدُوا عَنِ الصَّلاَةِ " . قَالَ أَبُو ذَرٍّ حَتَّى رَأَيْنَا فَىْءَ التُّلُولِ .
The Mu'adhdbin (the announcer of the hour of prayer) of the Messenger of Allah (ﷺ) called for the noon prayer. Upon this the Messenger of Allah (ﷺ) said: Let it cool down, let it cool down, or he said: Wait, wait for the intensity of heat is from the exhalation of Hell. When the heat is intense, delay the prayer till it becomes cooler. Abu Dharr said: (We waited) till we saw the shadow of the mounds.