56:76
Al-Waqi'ah 76
Surah Al-Waqi'ah (الواقعة), verse 76 — reference 56:76. Arabic text with optional translation and free audio on Al-Qalam.
وَإِنَّهُۥ لَقَسَمٌ لَّوْ تَعْلَمُونَ عَظِيمٌ
wa-innahu laqasamun law taʿlamūna ʿaẓīmun
And indeed, it is an oath - if you could know - [most] great.