Tafsir of At-Tur 52:46

(The Day their plotting will not avail them anything) meaning: nothing of avail. It is a substitute (badal) for "their day" (yawmihim).

It is not hidden that the focus on explaining the lack of benefit in their plotting requires that they actually utilize it, out of greed to benefit from it. This is nothing other than the plotting they devised regarding the affair of the Prophet (may Allah Almighty bless him and grant him peace), among which was their confrontation on the Day of Badr. As for the first blast [of the Trumpet], it is not among the things in which one engages in the defense of plotting and stratagems.

An answer was given to the first [objection] by denying that the swooning (al-sa'q) is restricted to the living; the dead also swoon, and they are included in the generality of "whoever" (man), even if their swooning is not like the swooning of the living in every respect. However, this is contrary to the apparent meaning and requires a sound textual proof.

An answer was given to the second [objection] by stating that it follows the pattern of the saying: "Upon a clear path, whose signposts no one can find." The meaning is: a day on which they have neither plotting nor avail. This is frequent in the Quran and is one of the doors of rhetoric and excellence.

It was said: It is the Day of Resurrection, and upon this is the majority [of scholars], though there is discussion regarding this.

It was also said: It is the day of their death. This was critiqued by stating that it has its problems, and furthermore, the [possessive] genitive construction (idafah), which implies their specific association with it, rejects it. So, do not be heedless.

(And they will not be helped) by anyone else in repelling the punishment from them.