'So on that Day the Event will occur' (69:15), meaning: the punishment will befall those who deserve the punishment.
﴿فَيَوْمئِذٍ وَقعت الْوَاقِعَة﴾ يَعْنِي: وَقَعَ الْعَذَابُ بِأَهْلِ الْعَذَابِ