Tafsir of Al-Muddathir 74:46

"And we used to deny the Day of Recompense."

That is, the Day of Retribution. They attributed the Day to Recompense, despite the fact that it contains calamities and terrors that have no end, because it is the most calamitous and terrifying of them all, and they are surrounded by it. The remaining calamities had already passed, and the delay in mentioning this particular crime of theirs—despite it being the greatest of them all—is for the sake of magnifying it. It is as if they said, "And after all of that, we were deniers of the Day of Resurrection." This is to clarify that their denial of it was concurrent with all their other enumerated crimes, and that it continued until the end of their lives, just as their statement testifies.