Tafsir of Al-Kahf 18:97

Hamza and Talha recited it by assimilating the ta into the ta'. This involves the conjunction of two quiescent letters in a manner contrary to the established rule; Abu Ali did not permit it, though a group of scholars did. Al-A'mash, via Abu Bakr, recited it as fa-ma ista'u (فما اصطاعوا), converting the sin into a sad due to the proximity of the ta'. Al-A'mash recited it as fa-ma istata'u (فما استطاعوا) with the ta intact, without omission.

The fa (in fa-ma) is fasihah (eloquent), meaning: "So when they did what they were commanded to do, whether it was the bringing of the molten copper or the actualizing of the task, he poured it over it, and it merged and adhered, one part to the other, until it became a solid mountain." Then Gog and Magog came and intended to climb it and pierce it, but fa-ma ista'u an yazharuhu—that is, they were unable to ascend it or climb upon it due to its height and smoothness. It is said that its height was two hundred cubits, and it is also said to be one thousand eight hundred cubits.

Wa-ma istata'u lahu naqba (وما استطاعوا له نقبا): They could not pierce it due to its hardness and thickness. It is said that its width was fifty cubits and its foundation had reached the water level. Within it, rock and molten copper had been placed, and the iron blocks were for the construction above ground.

It is not hidden that the pouring of molten copper over it—after the heat of the fire had affected it to the point that it became like fire, alongside the mention that the dam extended for one hundred farsakhs into the earth—could not be achieved except through a divine matter outside the ordinary course of nature. This includes the diversion of the intense heat of the fire away from the bodies of those working on the project; otherwise, such heat is, by nature, something no living creature could hover around. The same applies to the blowing [of air/bellows] upon those massive and numerous iron blocks until they became like fire.

It is possible that both of these matters were facilitated by strange instruments or techniques granted to him or to someone with him, which almost no one today knows. The sages of the past—and indeed even those of the modern era—possess wondrous techniques they achieve through strange instruments that almost transcend the bounds of reason; there is no doubt in this. Thus, what occurred for Dhu al-Qarnayn may be of that nature. It is said that its construction consisted of rocks joined to one another with iron hooks, with molten copper in their cavities, to the extent that not a single gap remained.

Ibn Jarir and Ibn Marduyah recorded from Abu Bakrah al-Thaqafi that a man said: "O Messenger of God, I have seen the dam of Gog and Magog." He asked, "Describe it to me." The man replied, "It is like striped Yemeni cloth, with black lines and red lines." He said, "You have seen it." The apparent meaning is that the sight was visual, not a dream, and this is a strange matter if the report is authentic.

As for what some have mentioned, that al-Wathiq Billah al-Abbasi sent Salam the Translator to discover this dam, and that he traveled toward the North in a long story until he saw it and then returned to report what he reported—the reliable historians deem this account weak. In my view, it is a fabrication, for it contains details that the verse rejects, as is not hidden to one who examines the verse in detail.

It is not hidden that the subtlety of bringing the ta in istata'u here [serves a specific purpose].