We prostrated ourselves along with the Messenger of Allah ﷺ on account of: "When the sky is rent asunder" and "Recite in the name of Your Lord Who created"
سَجَدْنَا مَعَ رَسُولِ اللَّهِ ﷺ فِي { إِذَا السَّمَاءُ انْشَقَّتْ } وَ { اقْرَأْ بِاسْمِ رَبِّكَ الَّذِي خَلَقَ }