Sahih Bukhari
768
Narrated Abu Rafi`: Once I prayed the `Isha' prayer with Abu Huraira and he recited, Idha s-samaa'u n-shaqqat (84) and prostrated. I said, What is that? He said, I prostrated behind Abul-Qasim, (the Prophet) (when he recited that Sura)..
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