Quran 77:14 from Surah Al-Mursalaat on Divine Marvels.
وَمَآ أَدۡرَىٰكَ مَا يَوۡمُ ٱلۡفَصۡلِ
English translation: And what will make you know what (is the) Day (of) the Judgment
Transliteration: wama adraka ma yawmu al-fasli