Tafsir of As-Sajdah 32:22

"And who is more unjust than he who..."

"Then" (thumma) in His saying: {Then he turns away from them} is for the purpose of expressing improbability (istib‘ād). The meaning is: turning away from the likes of the signs of Allah—in their clarity, illumination, and guidance to the straight path and the attainment of supreme happiness—after having been reminded of them, is something improbable in terms of reason and justice.

It is like saying to your companion: "You found such an opportunity, then you did not seize it," expressing disbelief at his failure to seize it. From this is the "then" in the verse from the Ḥamāsah:

He expresses disbelief that he would visit the depths of death after having seen them, become certain of them, and witnessed their intensity.

If you ask: Why was it not said, "Indeed, We are avengers upon him"?

I reply: Because He made him the most unjust of all the unjust, then threatened the criminals in general with vengeance. This indicates that the "most unjust" receives the greatest share of that vengeance. Had He used the pronoun [referring only to him], it would not have conveyed this benefit.

{And We certainly gave Moses the Scripture, so do not be in doubt over his meeting. And We made it a guidance for the Children of Israel. And We made from among them leaders guiding by Our command when they were patient and were certain of Our signs. Indeed, your Lord will judge between them on the Day of Resurrection concerning that over which they used to differ.}