al-Balad 90:20

ʿAlayhim nārun muʾṣada "Over them is a fire closed over."

This verse is almost the same as the last verse of Sūrat al-Humaza (innahā ʿalayhim muʾṣada — al-Humaza 104/8), and the analysis of that word was made there: the root ء-ص-د / و-ص-د, to shut a door, to close over; and the interpretation that the accumulating of wealth is the building of a closedness.

Two things have to be added here.

The first: the difference in the word order. In al-Humaza ʿalayhim had been brought before the predicate, and this conveyed emphasis. Here ʿalayhim is already at the head of the sentence and is the predicate; nārun muʾṣada is the subject. The structure is plainer.

The second: the two sūras ending with the same word. Al-Humaza related someone who accumulates wealth and closed with this word. Al-Balad relates someone who boasts of the wealth he has spent and closes with the same word. The two sūras tie two opposite relations with wealth to the same result.

And a contrast: throughout the sūra a verb of opening was treated — fakk, to loose a bond. In the last verse there is a closing — muʾṣada, closed over. The door is shut over the one who did not loose the bond on a neck.

I record this as my own reading; the opposition of the two roots, however, stands in the text.