Tafseer of The Constellations · Al-Burooj · 85:5
[Containing] the fire full of fuel,
Important: The Arabic source text is always authoritative. This translation is a study aid and has not been verified by scholars — do not use it as a basis for religious proof or for deriving rulings (ahkam). When in doubt, always consult the Arabic text and a qualified scholar.
And His statement: النَّارِ ذَاتِ الْوَقُودِ (The fire, supplied with fuel) (85:5). His word "the fire" (al-nār) is an appositive (badal) to "the trench" (al-ukhdūd), and for that reason it stands in the genitive. It was permissible to make it refer back to that as an appositive even though it is something other than it, because it was located within it; it was as if, since it was located within it, it were the same as the trench. Thus the construction of the sentence proceeded upon that basis, owing to the fact that those addressed knew its intended meaning. It was as if it had been said: slain were the people of the fire, supplied with fuel.
By His word ذَاتِ الْوَقُودِ (supplied with fuel) He means: supplied with thick, firm firewood. That is when one pronounces the wāw with a fatḥa (al-waqūd). As for "al-wuqūd" with a ḍamma on the wāw: that means the act of kindling itself.