Qur'an 7:167

وَإِذْ تَأَذَّنَ رَبُّكَ لَيَبْعَثَنَّ عَلَيْهِمْ إِلَىٰ يَوْمِ ٱلْقِيَـٰمَةِ مَن يَسُومُهُمْ سُوٓءَ ٱلْعَذَابِ ۗ إِنَّ رَبَّكَ لَسَرِيعُ ٱلْعِقَابِ ۖ وَإِنَّهُۥ لَغَفُورٌ رَّحِيمٌ

And (remember) when thy Lord proclaimed that He would raise against them till the Day of Resurrection those who would lay on them a cruel torment. Lo! verily thy Lord is swift in prosecution and lo! verily He is Forgiving, Merciful.