Tafsir of Az-Zumar 39:32

{Then, who is more unjust than one who lies about Allah} by attributing a partner or a child to Him, Glorified and Exalted is He, {and denies the truth}—that is, the matter which is the essence of rightness and the very truth, which is what the Prophet, may Allah bless him and grant him peace, brought—{when it has come to him}—that is, at the very moment of its arrival, without reflection or contemplation. Idh (when) here denotes suddenness, as explicitly stated by al-Zamakhshari. However, in al-Mughni, it is stipulated that this is only the case if it occurs after bayna or baynama, citing Sibawayh; thus, perhaps this is a predominant usage. It may also be said that the context necessitates this meaning regardless of whether idh denotes suddenness. The intent is that this liar who denies is more unjust than every other unjust person. {Is there not in Hell a dwelling for the disbelievers?}

{Is there not in Hell a dwelling...} for those who fabricated lies against Allah, Glorified is He, and hastened to deny the truth. The manifest noun (al-kafirin) is used in place of the pronoun to register them with disbelief. The plural takes into account the meaning of man (whoever), just as the singular in the preceding pronouns took into account its literal word form, or it refers to the genus of disbelief, thus encompassing the People of the Scripture, with these individuals being the primary subjects of the ruling. In any case, the meaning is that Hell is sufficient as a recompense for them, as if it were said: "Is Hell not sufficient for the disbelievers as a dwelling?" similar to His saying: {Hell is sufficient for them; they will burn in it}. This means it suffices as punishment for their disbelief and denial. Sufficiency is understood from the context, just as you might say to someone who asks for something: "Did I not bestow favor upon you?" meaning: My previous favor upon you is sufficient for you.

The verse has been used as evidence for declaring the people of innovation (ahl al-bid'ah) to be disbelievers, on the grounds that they deny what is known to be true. This has been countered by the argument that "whoever lies" refers specifically to those who lied to the prophets face-to-face during their proclamation, not absolutely, due to His saying: {when it has come to him}. Even if it were granted to be absolute, they are not deniers because they interpret [the texts]; and what they negate and deny is not necessarily known to be true by absolute necessity. For if it were known as a necessity of the religion, its rejector would be a disbeliever, like one who denies the obligatoriness of prayer and the like.

Al-Khafaji said: The most apparent meaning is that it refers to denying the prophets, peace be upon them, after the appearance of miracles, specifically regarding the fact that what they brought is from Allah—not absolute denial. It seems as though you would choose the position that one who interprets is not a denier; however, there is no excuse for an interpretation that denies what is known as a necessity of the religion.