(51) باب السُّجُودِ فِي { إِذَا السَّمَاءُ انْشَقَّتْ }
It was narrated that Abu Hurairah said:
"Abu Bakr and Umar prostrated during: 'When the heaven is split asunder,' as did the one who was better than them (the Prophet (ﷺ)). " (RU)
Reference (RU): Sunan an-Nasa'i 965 (RU)
In-book reference (RU): Book 11, Hadith 90 (RU)
English translation (RU): Vol. 2, Book 11, Hadith 966 (RU)