Mishkat al-Masabih
Anas said, “When we prayed behind the Prophet (ﷺ) at midday in summer we prostrated ourselves on our clothing to protect ourselves from the heat.” (Bukhari and Muslim, the wording being Bukhari’s.)
وَعَنْ أَنَسٍ قَالَ: كُنَّا إِذَا صَلَّيْنَا خَلْفَ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ بِالظَّهَائِرِ سَجَدْنَا على ثيابنا اتقاء الْحر
Reference