﴿ فَإِذَا جَآءَ وَعْدُ أُولَىٰهُمَا بَعَثْنَا عَلَيْكُمْ عِبَادًۭا لَّنَآ أُو۟لِى بَأْسٍۢ شَدِيدٍۢ فَجَاسُوا۟ خِلَٰلَ ٱلدِّيَارِ ۚ وَكَانَ وَعْدًۭا مَّفْعُولًۭا ﴾

“Hence, when the prediction of the first of those two [periods of iniquity] came true, We sent against you some of Our bondmen of terrible prowess in war, and they wrought havoc throughout the land: and so the prediction was fulfilled.”

Please check ayah 17:8 for complete tafsir.