﴿ ذَٰلِكَ جَزَآءُ أَعْدَآءِ ٱللَّهِ ٱلنَّارُ ۖ لَهُمْ فِيهَا دَارُ ٱلْخُلْدِ ۖ جَزَآءًۢ بِمَا كَانُوا۟ بِـَٔايَٰتِنَا يَجْحَدُونَ ﴾

“That requital of God’s enemies will be the fire [of the hereafter]: in it will they have an abode of immeasurable duration as an outcome of their having knowingly rejected Our messages.”

That severe chastisement and worst requital is the requital of God’s enemies jazā’u a‘dā’i the second hamza may be pronounced fully or replaced with a wāw — the Fire! al-nāru an explicative supplement to jazā’u ‘the requital’ alluded to by the demonstrative dhālika ‘that’. Therein will be their everlasting abode that is as a place of permanent residence from which there will be no removal as a requital jazā’an is in the accusative as a verbal noun from the implicit verbal action for their denial of Our signs for their denial of the Qur’ān.