Quran 54:46 from Surah Al-Qamar on Divine Marvels.
بَلِ ٱلسَّاعَةُ مَوۡعِدُهُمۡ وَٱلسَّاعَةُ أَدۡهَىٰ وَأَمَرُّ
English translation: Nay the Hour (is) their promised time and the Hour (will be) more grievous and more bitter
Transliteration: bali al-sa'atu maw'iduhum wal-sa'atu adha wa-amarru