Sunan Abi Dawud, Hadith 1403 ⓘ
Narrated 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.
حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا الْمُعْتَمِرُ، قَالَ سَمِعْتُ أَبِي، حَدَّثَنَا بَكْرٌ، عَنْ أَبِي رَافِعٍ، قَالَ صَلَّيْتُ مَعَ أَبِي هُرَيْرَةَ الْعَتَمَةَ فَقَرَأَ { إِذَا السَّمَاءُ انْشَقَّتْ } فَسَجَدَ فَقُلْتُ مَا هَذِهِ السَّجْدَةُ قَالَ سَجَدْتُ بِهَا خَلْفَ أَبِي الْقَاسِمِ صلى الله عليه وسلم فَلاَ أَزَالُ أَسْجُدُ بِهَا حَتَّى أَلْقَاهُ .
also referenced under: Hadith 1408 (DarusSalam) & Book 7, Hadith 1403 (USC-MSA)