Quran 23:77 from Surah Al-Muminoon on Divine Marvels.
حَتَّىٰٓ إِذَا فَتَحۡنَا عَلَيۡهِم بَابٗا ذَا عَذَابٖ شَدِيدٍ إِذَا هُمۡ فِيهِ مُبۡلِسُونَ
English translation: Until when We opened for them a gate of a punishment of a punishment severe behold They in it (will be in) despair
Transliteration: hatta idha fatahna alayhim baban dha adhabin shadidin idha hum fihi mub'lisuna