Malik related to us from Abdullah ibn Yazid the mawla of al-Aswadibn Sufyan, from Abu Salama ibn Abd ar-Rahman from Muhammad ibn Abdar-Rahman ibn Thawban from Abu Hurayra that the Messenger of Allah,may Allah bless him and grant him peace, said, "When the heat isfierce delay the prayer until it gets cooler, for scorching heat is apart of the blast of Jahannam."He added, "The Firecomplained to its Lord, so He allowed it two breaths in each year, abreath in winter and a breath in summer."
App reference: Book 1, Hadith 28
USC-MSA web (English) reference: Book 1, Hadith 28
Arabic reference: Book 1, Hadith 29