فَمَا اسطاعوا أَن يَظهَروهُ وَمَا استَطاعوا لَهُ نَقبًا

So they could neither scale it, nor could they make a hole in it.

EXEGESIS

Isṭāʿū (could) and istaṭāʿū (could) are both from the verb istaṭāʿa meaning to be able to do something. Because the t and ṭ are considered to be vocalised from the same source (makhraj) them following each other is considered heavy and therefore istaṭāʿa can also be pronounced in the contracted forms of isṭāʿa and istāʿa as well.^{‎[1]Tibyan, 7/93-94.} It is said this is done with the word istaṭāʿa because it is a very commonly used word.^{‎[2]Tabari, 16/22.}

This similar usage was seen in verses 67, 72, 78, and 82. As we mentioned in verse 82, it could also be considered that the contracted, ‘lighter’ form of the verb is meant to convey something slightly easier in comparison to the ‘heavier’ form. In this case, scaling the wall would be a much simpler task than making a hole in the thick, hardened metal.

EXPOSITION

There is some omission in the story once again and we understand that the wall was completed successfully.^{‎[3]Mizan, 13/365.}

So they: this refers to Gog and Magog.^{‎[4]Mizan, 13/365.}

Could neither scale it: because of the height of the wall and its flat and smooth surface.^{‎[5]Zamakhshari, 2/748; Mizan, 13/365.}

Nor could they make a hole in it: because of its hardness and toughness.^{‎[6]Zamakhshari, 2/748; Mizan, 13/365.}

[1] Tibyan, 7/93-94.
[2] Tabari, 16/22.
[3] Mizan, 13/365.
[4] Mizan, 13/365.
[5] Zamakhshari, 2/748; Mizan, 13/365.
[6] Zamakhshari, 2/748; Mizan, 13/365.