حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ عَطَاءِ بْنِ يَسَارٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏"‏ إِنَّ شِدَّةَ الْحَرِّ مِنْ فَيْحِ جَهَنَّمَ فَإِذَا اشْتَدَّ الْحَرُّ فَأَبْرِدُوا عَنِ الصَّلاَةِ ‏"‏ ‏.‏ وَقَالَ ‏"‏ اشْتَكَتِ النَّارُ إِلَى رَبِّهَا فَقَالَتْ يَا رَبِّ أَكَلَ بَعْضِي بَعْضًا ‏.‏ فَأَذِنَ لَهَا بِنَفَسَيْنِ فِي كُلِّ عَامٍ نَفَسٍ فِي الشِّتَاءِ وَنَفَسٍ فِي الصَّيْفِ ‏"‏ ‏.‏

Yahya related to me from Malik from Zayd ibn Aslam from Ata ibnYasar that the Messenger of Allah, may Allah bless him and grant himpeace, said, "Scorching heat is a part of the blast of Jahannam. So,when the heat is fierce, delay the prayer until it gets cooler." He added in explanation, "The Fire complained to its Lord andsaid, 'My Lord, part of me has eaten another part,' so He allowed ittwo breaths in every year, a breath in winter and a breath in summer." Translation Not Available

Book Ref: Muwatta Imam Malik Book 1 Hadith 27
Web Ref:  Muwatta Imam Malik Book 1 Hadith 27