The Messenger of Allah ﷺ said, "When the heat becomes intense, delay the prayer until it cools down, for the intensity of heat is from the blazing breath of Hell."
حدثنا سفيان عن الزهري عن سعيد
قال رسول الله ﷺ إذا اشتد الحر فأبردوا بالصلاة فإن شدة الحر من فيح جهنم
Its isnad is sahih, and it is a repetition of no. 2130 with the same meaning. As for his saying, "the fayh of Hell," Ibn Athir said, "Fayh means the intense heat blazing forth and boiling over."