What was the action taken by Abu Rafi' when he heard the Prophet Muhammad (saw) recite Sura 84?
 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) and I will go on doing it till I meet him."