Word by Word Analysis

وَتَحْسَبُهُمْ أَيْقَاظًا وَهُمْ رُقُودٌ ۚ وَنُقَلِّبُهُمْ ذَاتَ ٱلْيَمِينِ وَذَاتَ ٱلشِّمَالِ ۖ وَكَلْبُهُم بَـٰسِطٌ ذِرَاعَيْهِ بِٱلْوَصِيدِ ۚ لَوِ ٱطَّلَعْتَ عَلَيْهِمْ لَوَلَّيْتَ مِنْهُمْ فِرَارًا وَلَمُلِئْتَ مِنْهُمْ رُعْبًا 18

And you would think them awake, while they were asleep. And We turned them to the right and to the left, while their dog stretched his forelegs at the entrance. If you had looked at them, you would have turned from them in flight and been filled by them with terror.