﴿ كَذَّبَ ٱلَّذِينَ مِن قَبْلِهِمْ فَأَتَىٰهُمُ ٱلْعَذَابُ مِنْ حَيْثُ لَا يَشْعُرُونَ ﴾

“Those who lived before them did [too] give the lie to the truth - whereupon suffering befell them without their having perceived whence it came:”

Those who were before them denied their messengers with regard to the coming of the chastisement; and so the chastisement came on them whence they were not aware in a way that would never have occurred to them.