Surah 82. Al-Infitar, Ayah 15

I understand this relative clause to govern "the Fire", i.e., the Punishment. It will be postponed as long as possible, to give the Sinner every chance of repentance and amendment. But once the period of probation is past, it will be irrevocable. There will be no going back from it. By inference, the Righteous may individually reach some stage of Bliss at once, possibly in this life, possibly after death, though the Final Judgment will be the general and complete cessation of this fleeting world and the creation of the world of Eternity.