Abu Dawud Book 2, Hadith Number 1403.
Chapter : Prostration in suras inshiqaq (84) and iqra (96).
Narated By Abu Rafi’ : I offered the night prayer behind Abu Hurairah. Hr recited Surah Inshiqaq (“When the sky is rent asunder”) and prostrated himself. I asked him: What is prostration? He replied: I prostrated myself on the account of this (surah) behind Abu al_Qasim (PBUH). I shall continue prostrating on account of this till I meet him.