Sahih Bukhari | Volume 1 | Hadith Number 735
Narrated by Abu Rafi'
Once I prayed the 'Isha prayer with Abu Huraira and he recited, "Idha-s-Sama' u- nShaqqat" (84) and prostrated. I said, "What is that?" He said, "I prostrated behind Abu-l- Qasim, (the Prophet) (when he recited that Sura) and I will go on doing it till I meet him."