But those who believe and do righteous deeds - We will admit them to gardens beneath which rivers flow, wherein they abide forever. For them therein are purified spouses, and We will admit them to deepening shade.
The Punishment of Those Who Disbelieve in Allah's Books and Messengers
Allah describes the torment in the Fire of Jahannam for those who disbelieve in His Ayat and hinder from the path of His Messengers. Allah said,
إِنَّ الَّذِينَ كَفَرُواْ بِـَايَـتِنَا
(Surely, those who disbelieved in Our Ayat ,) meaning, We will place them in the Fire which will encompass every part of their bodies. Allah then states that their punishment and torment are everlasting,
(We shall burn them in Fire. As often as their skins are roasted through, We shall change them for other skins that they may taste the punishment). Al-A`mash said that Ibn `Umar said, "When their skin are burned, they will be given another skin in replacement, and this skin will be as white as paper." This was collected by Ibn Abi Hatim, who also recorded that Al-Hasan said,
Particular believers and disbelievers were mentioned in the previous verses. Stated now is the reward and punishment of a believer and a disbeliever as a universal rule.
Commentary
Explaining the highly apocalyptic statement كُلَّمَا نَضِجَتْ جُلُودُهُم بَدَّلْنَاهُمْ in verse 56, Sayyidna Mu` adh ؓ says that as soon as their skin is burnt out it will be replaced - and this will be with such speed that the skin will be replaced a hundred times in one moment.
Sayyidna Hasan al-Basri (رح) says:
تاکل النار کلّ یوم سبعین الف مرّۃ کلما اکلتھم قیل لھم : عودوا فیعودون کما کانوا (اخرج البیھقی عین الحسن بحوالہ مظھری ج 2)
In real life, the hypocrites tread the path of selfish desires and give in to satanic inducements, but outwardly, bearing the label of religion, they think that their actions are truly guided by God’s religion. In such an atmosphere, whenever the pure Truth is presented to them, they become its bitterest opponents. They feel that their religious status is being negated by that call. On the other hand, the existence of non-believers around them poses no such challenge and, therefore, their attitude towards them remains lax. But the preacher of truth cannot expect any leniency from them, for they become infuriated with jealousy over someone else having been granted religious representation, when they alone had formerly had a monopoly of religion. They quite forget that God chooses the representatives of His religion on the basis of purity of soul, inner piety and a sound heart, and not because of any outward show of piety. Being accursed is to be deprived of the grace and succour of God. Just as starvation and thirst wreck one’s physical existence, similarly deprivation of God’s grace and succour wrecks one’s spiritual existence. A cursed person becomes so insensitive that he loses the ability to distinguish between truth and untruth. He fails to recognize and accept explicit signs and cannot differentiate between absurd argumentation and logical argument.
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.