Surah Al-A'raf, ayah 167

وَإِذۡ تَأَذَّنَ رَبُّكَ لَيَبۡعَثَنَّ عَلَيۡهِمۡ إِلَىٰ يَوۡمِ ٱلۡقِيَٰمَةِ مَن يَسُومُهُمۡ سُوٓءَ ٱلۡعَذَابِۗ إِنَّ رَبَّكَ لَسَرِيعُ ٱلۡعِقَابِ وَإِنَّهُۥ لَغَفُورٞ رَّحِيمٞ ١٦٧

Wa idh ta'addhana rabbuka layab'athanna 'alayhim ilā yawmil-qiyāmati man yasūmuhum sū'al-'adhābi inna rabbaka lasarī'ul-'iqābi wa innahū laghafūrur rahīm

And [mention] when your Lord declared that He would surely [continue to] send upon them until the Day of Resurrection those who would afflict them with the worst torment. Indeed, your Lord is swift in penalty; but indeed, He is Forgiving and Merciful.