Tafseer Ibn Kathir of AL KAHFI [87]

قَالَ أَمَّا مَن ظَلَمَ فَسَوْفَ نُعَذِّبُهُ ثُمَّ يُرَدُّ إِلَى رَبِّهِ فَيُعَذِّبُهُ عَذَابًا نُّكْرًا

He said, "As for one who wrongs, we will punish him. Then he will be returned to his Lord, and He will punish him with a terrible punishment.