Sahih al-Bukhari Book 10, Hadith 25
I came to the Prophet (ﷺ) with some men from my tribe and stayed with him for twenty nights. He was
kind and merciful to us. When he realized our longing for our families, he said to us, "Go back and
stay with your families and teach them the religion, and offer the prayer and one of you should
pronounce the Adhan for the prayer when its time is due and the oldest one amongst you should lead
the prayer."
The prophet said, "There is a prayer between the two Adhans (Adhan and Iqama), there is a prayer between the two Adhans." And then while saying it the third time he added, "For the one who wants to (pray).
We were in the company of the Prophet (ﷺ) on a journey and the Mu'adh-dhin wanted to pronounce the Adhan for the (Zuhr) prayer. The Prophet (ﷺ) said to him, "Let it become cooler." Then he again wanted to pronounce the Adhan but the Prophet; said to him, "Let it become cooler." The Mu'adh-dhin again wanted to pronounce the Adhan for the prayer but the Prophet (ﷺ) said, "Let it become cooler," till the shadows of the hillocks become equal to their sizes. The Prophet (ﷺ) added, "The severity of the heat is from the raging of Hell."