Sahih al-Bukhari 538
Book 9: Times of the Prayers · Narrated by Abu Sa`id
Arabic
حَدَّثَنَا عُمَرُ بْنُ حَفْصٍ، قَالَ حَدَّثَنَا أَبِي قَالَ، حَدَّثَنَا الأَعْمَشُ، حَدَّثَنَا أَبُو صَالِحٍ، عَنْ أَبِي سَعِيدٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " أَبْرِدُوا بِالظُّهْرِ، فَإِنَّ شِدَّةَ الْحَرِّ مِنْ فَيْحِ جَهَنَّمَ ". تَابَعَهُ سُفْيَانُ وَيَحْيَى وَأَبُو عَوَانَةَ عَنِ الأَعْمَشِ.
English translation
Narrated Abu Sa`id:that Allah's Messenger (ﷺ) said, "Pray Zuhr prayer when it becomes (a bit) cooler as the severity of heat is from the raging of the Hell-fire
Reference: Sahih al-Bukhari 538, Book of Times of the Prayers. English translation by Dr. Muhammad Muhsin Khan.