43:33 — "And were it not that mankind would become one community [of disbelievers], We would have made for those who disbelieve in the Most Merciful—for their houses—ceilings of silver and stairways upon which they mount."
This is a resumption of speech, clarifying the insignificance of worldly possessions and their low value in the sight of Allah, the Exalted and Majestic. The meaning is that the status of worldly possessions is so lowly that, were it not for the aversion to mankind uniting upon disbelief and adhering to it, We would have bestowed it in its most perfect form upon the most wicked of creation and those of the lowest station. Thus, the aversion to a consensus upon disbelief is what prevents the bestowing of enjoyment upon every disbeliever and the expansion of their wealth, not that worldly goods have any value to Us.
The aforementioned aversion is the aspect of wisdom in refraining from enriching every disbeliever and expanding their provision; there is no impropriety in postulating this. This is not predicated upon the necessity of observing "public interest" or the "will for faith" from the creation, as some have erroneously supposed. It seems that the reason why expanding wealth upon the disbelievers would be a cause for uniting upon disbelief is the intense love people have for the world; for when they see that, they would disbelieve in order to attain it. This is based on the meaning that Allah, the Exalted is His majesty, knew that if He were to do that, their love for the world at that moment would drive people to disbelief. Therefore, it cannot be said: "Many people today would attain complete wealth if they were to disbelieve, even if they were coerced into it by the threat of death." The intended meaning of the "one matter"—which is required by them being a "one community"—is, by the context of the answer, disbelief.
"For their houses" (li-buyutihim) is a substitution of inclusion (badal al-ishtimal) for His saying "for those who disbelieve" (liman yakfuru). The lam (preposition) in both serves to denote specification (ikhtisas), or they are both attached to the verb, not on the basis of substitution; the lam in "for those" (liman) is connected to the verb because it is transitive via the lam, thus serving as the object of the verb. The lam in "for their houses" (li-buyutihim) is for causality (ta’lil), serving as the maf'ul lahu (dative of reason). It is also permissible that the first lam denotes ownership and the second denotes specification, as in your saying: "I gifted the rope to Zayd for his beast." Ibn Atiyyah favored this. It is not permissible, upon assuming the two lams differ in meaning, to posit substitution, for the requirement of repeating the operative word in substitution is unity of meaning. Abu Hayyan leaned toward this. Al-Khafaji said: There is no obstacle to substituting the whole for the whole without considering a repetition.
Suqufan (ceilings) is the plural of saqf, like ruhun (pledges) is the plural of rahn. It is narrated from Al-Farra’ that it is the plural of saqfiyyah, like sufun (ships) is the plural of safinah.
Ma'arij (stairways) is the plural of ma'raj (stairway), and it is conjoined to "ceilings" (suqufan). That is, "We would have made for them ascents upon which they would climb to the roofs and upper chambers." It is as if the meaning were "stairways of silver," based on the fact that the conjunction is evidently indicative of sharing in the restriction (of being silver), even if it (the descriptor) preceded it. Abu Hayyan said: This is not necessarily fixed.
Abu Raja’ read suqfan with a damma on the sin and a sukūn on the qaf as a simplification (takhfif), and in al-Bahr, it is stated that this is the dialect of Tamim. Ibn Kathir and Abu ‘Amr read it with a fatha on the sin and a sukūn on the qaf as a singular form, because it is a generic noun applicable to the singular and what is above it, which is the intended meaning in the context of "houses." It has also been read with a fatha on both the sin and the qaf, which is a dialectal variation of saqf; this is not a movement of a quiescent letter, as there is no basis for that.
It was also read as suqufan (suqufan), which is the plural of saqf, like fulus (coins) is the plural of fals. Talha read it as ma'arij (with a long vowel), which is the plural of mi'raj.