اقرأ وتدبر الآية 2237 من سورة سُورَةُ الكَهۡفِ: فَمَا اسْطَاعُوا أَنْ يَظْهَرُوهُ وَمَا اسْتَطَاعُوا لَهُ نَقْبًا
فَمَا اسْطَاعُوا أَنْ يَظْهَرُوهُ وَمَا اسْتَطَاعُوا لَهُ نَقْبًا
And thus [the rampart was built, and] their enemies were unable to scale it, and neither were they able to pierce it.