your lord has announced that he would send against them until the day of resurrection those who would inflict terrible suffering upon them. your lord is swift in retribution yet he is forgiving and merciful.
وإذ تأذن ربك ليبعثن عليهم إلى يوم القيامة من يسومهم سوء العذاب إن ربك لسريع العقاب وإنه لغفور رحيم