"Allah's Messenger 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 Allah's Messenger 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. Allah's Messenger said: 'The severity of heat is from the raging of Hell, so wait until it becomes cooler for the (Zuhr) prayer.'"
حَدَّثَنَا مَحْمُودُ بْنُ غَيْلاَنَ، حَدَّثَنَا أَبُو دَاوُدَ الطَّيَالِسِيُّ، قَالَ أَنْبَأَنَا شُعْبَةُ، عَنْ مُهَاجِرٍ أَبِي الْحَسَنِ، عَنْ زَيْدِ بْنِ وَهْبٍ، عَنْ أَبِي ذَرٍّ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ فِي سَفَرٍ وَمَعَهُ بِلاَلٌ فَأَرَادَ بِلاَلٌ أَنْ يُقِيمَ فَقَالَ " أَبْرِدْ " . ثُمَّ أَرَادَ أَنْ يُقِيمَ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " أَبْرِدْ فِي الظُّهْرِ " . قَالَ حَتَّى رَأَيْنَا فَىْءَ التُّلُولِ ثُمَّ أَقَامَ فَصَلَّى فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِنَّ شِدَّةَ الْحَرِّ مِنْ فَيْحِ جَهَنَّمَ فَأَبْرِدُوا عَنِ الصَّلاَةِ " . قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ .
Tirmizi
The Book on Salat (Prayer) • Hadith 158