فَٱلْمُورِيَٰتِ قَدْحًا
The sūra uses فَ at the head of verses 2, 3, 4 and 5. This is the fāʾ al-taʿqīb: it gives the sense immediately after. ثُمَّ (then) puts time in between; وَ conveys no order; فَ builds an unbroken continuity.
Four fāʾs in four verses. The scene flows without a break. This is exactly the rhythm one expects in the telling of a raid: no halt.
Note this — the oath itself began with a wāw, but all the transitions inside it are made with a fāʾ. That is, the thing sworn by is a single thing; the five verses are five moments of that one thing, not five separate objects. For this reason the grammarians count the five verses as a single oath.
Root: و-ر-ي. Warā'l-zandu — fire came out of the fire-stick. أَوْرَى (Form IV) — he brought fire out, he kindled the fire.
The zand is the two-piece fire-making set the Arabs used to light a fire: a spark is obtained by rubbing or striking the one against the other. The Qurʾān mentions this operation directly:
"Have you considered the fire that you kindle? Was it you who brought its tree into being, or are We the bringer?" (al-Wāqiʿa 56/71-72)
The verb there is this verb. That is, in the Qurʾān's own usage the word describes the operation of bringing fire out of stone or out of wood.
Root: ق-د-ح. Qadaḥa'l-zanda — he struck the fire-stick, he rubbed it. مِقْدَحَة — the fire-striking implement. At the centre of the root there is a hard blow.
The verse sets these two words side by side: al-mūriyāti qadḥā — those that bring out fire by striking. The hoof striking the stone, and a spark born of the strike.
A natural inference is drawn from this, and most of the exegetes draw it: a spark is seen in the dark. By day the spark of a hoof goes unnoticed. That is, the second verse says that the scene passes at night — and the third verse will bring the morning. Between the two verses there is a line of time: travelling through the night, arrival towards dawn.
The Qurʾān uses this reversal elsewhere too: "It is He who brings you fire out of the green tree" (Yā Sīn 36/80) — fire out of what is moist, that is, out of the opposite of fire. Here it is out of stone: out of what is cold and dead.
This stands not as a point of exegesis but as an observation; but since in the later verses of the sūra it will be asked what dry soil (kanūd) and dead graves yield, it is worth keeping in mind.