Quran 18:18 Al-Kahf, ayah 18 of 110

وَتَحْسَبُهُمْ أَيْقَاظًا وَهُمْ رُقُودٌ ۚ وَنُقَلِّبُهُمْ ذَاتَ ٱلْيَمِينِ وَذَاتَ ٱلشِّمَالِ ۖ وَكَلْبُهُم بَـٰسِطٌ ذِرَاعَيْهِ بِٱلْوَصِيدِ ۚ لَوِ ٱطَّلَعْتَ عَلَيْهِمْ لَوَلَّيْتَ مِنْهُمْ فِرَارًا وَلَمُلِئْتَ مِنْهُمْ رُعْبًا ۝١٨

18:18 And thou wouldst have deemed them waking though they were asleep, and We caused them to turn over to the right and the left, and their dog stretching out his paws on the threshold. If thou hadst observed them closely thou hadst assuredly turned away from them in flight, and hadst been filled with awe of them.