Tafsir of Al-Inshiqaq 84:25

{Except for those who believed and did righteous deeds} is a disjunctive exception (istithna' munqati') from the pronoun in {give them glad tidings}. It is also permissible for it to be a conjunctive exception (istithna' muttasil), on the premise that what is intended by the excepted ones are those who believed and acted righteously after [having been] among them—meaning, among those disbelievers. The past tense in both verbs is considered according to the foreknowledge of Allah the Exalted, or they are meant in the sense of the present tense. It is not hidden that there is affectation (takalluf) in this, especially since the first [interpretation] is more suitable to His saying, the Exalted: {they shall have a reward unfailing}, for the mentioned reward is not exclusive to the believers among them, but [applies] to all believers. The notion that the exclusivity is relative to those remaining in disbelief among them is contrary to the apparent meaning, although the mere implication of exclusivity to the believers among them is sufficient for the purpose, as is not hidden.

The tanwin in {reward} (ajr) is for exaltation. The meaning of {unfailing} (ghayr mamnun) is "not severed," from manna when it means to cut. Alternatively, it means "not reckoned or held against them," from manna 'alayhi when one counts a favor and calculates it. Some scholars have attributed this meaning of manna to the root meaning of "to cut" as well, on the basis that it cuts off the blessing and necessitates the cessation of gratitude for it.

The sentence, according to what has been said, is an isti'naf (a new introductory clause) confirming what the exception has imparted regarding the negation of punishment for those mentioned, and clarifying its nature and its accompaniment by a great, abundant reward.