Sunan Abi Dawud 1408
سنن أبي داود#1408SahihNarrated Abu Rafi':I offered the night prayer behind Abu Hurairah. He recited Surah Inshiqaq ("When the sky is rent asunder") and prostrated himself. I asked him: What is this prostration ? He replied: I prostrated myself on account of this (surah) behind Abu al-Qasim (i.e. the Prophet). I shall continue prostrating on account of this till I meet him
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Shuaib Al ArnautSahih
Zubair Ali ZaiSahih Bukhari (1078) Sahih Muslim (578)
In-book reference: 7:8