Tafsir of Al-Kahf 18:95

{What my Lord has established me in is better} That is, the state of power, wealth, and ease in which my Lord has placed me is better than the tribute you offer me. I have no need for it, just as Solomon (peace be upon him) said: {What Allah has given me is better than what He has given you} (An-Naml: 36). It is recited both with and without assimilation (idgham).

{So assist me with strength} With labor, craftsmen skilled in construction and work, and with tools.

{A barrier (radm)} A fortified, reinforced partition. A radm is greater than a sadd (dam), derived from the expression "a patched garment" (thawb mardum), meaning patches upon patches.

It is said: He dug the foundation until he reached water, then laid the foundation with rock and molten copper, and the structure with blocks of iron, placing firewood and charcoal between them until he filled the space between the two mountains up to their summits. Then he placed bellows until it became like fire, and he poured molten copper over the heated iron, so it fused and adhered to one another, becoming a solid mountain. It is said the distance between the two mountains is one hundred leagues.

It is recited as suwan and suwan. It is narrated from the Messenger of Allah (peace be upon him) that a man told him about it, and he asked, "How did you see it?" The man replied, "Like a striped garment, with a black stripe and a red stripe." He said, "You have indeed seen it."

{The two sides (as-sadafayn)} The two sides of the mountains, because they face each other (yatasadafan). It is also recited as as-sudufayn (two dammahs), as-sudfayn (damma and sukun), and as-sadafayn (fatha and damma).

{Molten copper (qitr)} Molten copper, because it drips (yaqturu). Qitran is in the accusative case because it is the object of afrigh (I shall pour). The meaning is: "Bring me copper, I shall pour copper upon it." The first is omitted because the second indicates it. It is also recited as i'tuni (bring me), meaning "come to me."

{So they were not able (fama istaṭa'u)} The ta is omitted for lightness, as the ta is close in articulation to the ta. It is also recited as fama ista'u (with the sin changed to sad). As for those who recite it by assimilating the ta into the ta, it is a meeting of two consonants that does not follow the standard rule.

{To scale it (an yadhharuhu)} That is, to climb it. They have no means to ascend it due to its height and smoothness, nor to pierce it due to its hardness and thickness.

{He said: "This is a mercy from my Lord; but when the promise of my Lord comes, He will make it level (dukka), and the promise of my Lord is ever true."}