COMMENTARY on 78:40
Mustafa Khattab:

Translation:
Indeed, We have warned you of an imminent punishment—the Day every person will see ˹the consequences of˺ what their hands have done, and the disbelievers will cry, “I wish I were dust.”4
Commentary:
4   In the Hereafter, Allah will judge between all of His creation including animals, which will eventually become dust. The wicked will wish that they too were turned into dust so they do not have to go to the Fire, as reported in an authentic narration collected by Al-Ḥakim.

 

A. Yusuf Ali:

Translation:
Verily, We have warned you of a Penalty near- 5914 the Day when man will see (the deeds) which his hands have sent forth, and the Unbeliever will say, "Woe unto me! Would that I were (metre) dust!" 5915
Commentary:

5914  Is Judgement very near? Yes. There are three stages of Judgement (1) Many of our sins and wrongdoings find their penalty in this very life. It may not be an open or striking event, but it corrodes the soul and conscience all the time. Let us therefore turn back to Allah in repentance and ask for forgiveness (2) Where the Penalty is not actually perceived or is not visible in this life, Death is considered the Lesser Judgement for each individual soul: see n. 5822 to 75:22. Death may come to anyone at any time, and we must all be ready for it. (3) Then there is the final Judgement, when the whole of the present order passes away, and there is a New World . Time as we know it will not exist. Fifty thousand years as we reckon now will be but as a Day; 70:4. According to those standards even this Final Judgement is quite near, and we must prepare for it. For it will be too late then for repentance.

5915  The Unbeliever, the Rejecter of Allah, will then find himself in a world of absolute Reality, in which there will be no place for him. He will neither live nor die: 20:74. He will wish that he could be reduced to nothingness, but even that would not be possible. @@@

 

Muhammad Asad:

Translation:
Verily, We have warned you of suffering near at hand - [suffering] on the Day when man shall [clearly] see what his hands have sent ahead, and when he who has denied the truth shall say, "Oh, would that I were mere dust... !" 21
Commentary:
21  Cf. 69:27.