The chapter
"Then watch for the Day the sky brings a visible smoke, covering the people, this is a painful punishment. 'Our Lord, remove from us the punishment; indeed, we are believers.'" Surat ad-Dukhan holds the sign in four verses shaped like a dialogue: the sky produces; mankind pleads; and the answer arrives with the coldest question in the Qur'an: "How can there be reminder for them, when a clear Messenger already came to them, and they turned away?"
The Codex records both layers of the exegesis, because the companions themselves held both. Ibn Mas'ud read the smoke as already fulfilled: the famine Quraysh suffered after the Prophet's ﷺ du'a, when a man looked at the sky and saw something like smoke from hunger, and he anchored it to the verse's continuation, "We will remove the punishment a little; you will revert." Others among the companions and the majority of later scholarship held the smoke to be a still-future sign of the Hour, and this is fixed by the hadith of Hudhayfah ibn Asid in Sahih Muslim, where the Prophet ﷺ counts the Ten and names the smoke among them, in the same breath as the Dajjal and the sun from the west. Both readings can stand: a near fulfillment as a specimen, a far fulfillment as the sign itself, a pattern the Qur'an uses elsewhere, and the Codex flags honestly rather than flattening.
As a sign of the End, its distinguishing feature is totality of exposure: "covering the people", yughshan-nas, no bunker, no border, no altitude. The reports describe the believer affected as with a cold, while it settles on the denier, a physical event with a moral filter, like the Dabba's mark and unlike any natural catastrophe. Its position among the heavenly signs continues the sequence's logic: after the verdicts are printed, the atmosphere itself begins shutting down the stage.
The du'a embedded in the surah: "Our Lord, remove it; we believe", is the sequence's recurring tragedy: right words, wrong tense. It is the plea of Pharaoh in the water, of the world at the western dawn, scheduled once more under a smoking sky. The Qur'an placed the correct timing of those exact words in every reader's hands, centuries in advance, at the price of reading them one node early.
After the smoke, the book of warnings is nearly closed: the earth begins to give way beneath the deniers' cities, and the sequence accelerates, beads, as he ﷺ said, falling from a cut string.