Tafsir of Al-Mu'minoon 23:40

(He said): God—Exalted is He—said this in response to his supplication and as a promise regarding what he requested:

(In a little while): That is, after a short amount of time. The ma (in ‘amma) is an extra particle inserted between the preposition and its object to emphasize the meaning of smallness. Qalil (little) is an adjective for a noun (zaman - time) that has been omitted, with the adjective serving as a sufficient substitute for it; this construction is frequent. It has also been suggested that ma is an indefinite noun (nakirah tamma) and qalil is a substitute (badal) for it, or that ma is an indefinite noun described by qalil. The preposition ‘an here carries the meaning of "after," and it is connected to His—Exalted is He—saying: "(they will surely become regretful)."

Its connection to both the verb and the description is possible. This is permissible despite the intervention of the oath-particle (lam), because a prepositional phrase, like an adverb, allows for a level of latitude that others do not.

Abu Hayyan said: The majority of our colleagues hold that the object of the verb following the oath-particle cannot precede the particle itself, whether it is an adverb, a prepositional phrase, or otherwise. According to this view, the phrase is connected to an implied verb indicated by what precedes it; the estimation would be "In a little while you shall be aided," or connected to what follows it, i.e., "they shall become, in a little while, regretful," and so on. The position of al-Farra’ and Abu ‘Ubaydah is that it is permissible to move the object of a verb governed by this lam to a position before the lam absolutely.

(They will become): Meaning, they will turn into; that is, by God—Exalted is He—they will certainly become regretful for what they have done in terms of denial after a short time. This refers to the moment the torment descends in this world and they witness it. It has also been said that it refers to the time after death.

In al-Lawami’, it is reported from some that it is read as (latusbihunna) with a ta’ (addressing the second person). If one were to argue that the speech is from the Messenger to the disbelievers after his prayer was answered, it would be permissible.