Musannaf Ibn Abi Shayba 3:908

Ibn ‘Ulayyah narrated to us, from al-Jurayri, from ‘Urwah, from ‘Abdullah ibn Shaqiq, from Abu Hurayrah: He said: The heat, or the intensity of the heat, is from the scorching breath of Hell, so cool down [by delaying] the Dhuhr prayer.