The Messenger of Allah ﷺ said, "When the heat becomes intense, delay the prayer until it cools down, for the intensity of the heat is from the blast of Hell."
حدثنا عبد الرزاق حدثنا معمر وابن جريج عن الزهري عن ابن المسيب وأبي سلمة
قال رسول الله ﷺ إذا اشتد الحر فأبردوا عن الصلاة فإن شدة الحر من فيح جهنم
Its isnad is sahih, and its meaning has already appeared through several routes from Abu Hurairah at 7130, 7245, 7267.His saying, "so cool down from the prayer," matches some of the wordings in Bukhari according to the narration of Kashmihini. Hafiz said in Fath al-Bari 2:14, "It has been said that ['an] is also superfluous, or that ['an] carries the meaning of 'with,' or that it denotes transgression, meaning delay it past its usual time until the intensity of the heat breaks. What is meant by 'the prayer' is Dhuhr, since it is the prayer during which the heat is generally most intense at the beginning of its time, and this has come explicitly in the hadith of Abu Saeed."