Living in Hell for ever
As it is mentioned in the Koranic verses, Hell as well as the Heaven has an eternal aspect, meaning those who deserve severe torments will live in Hell for ever as their punishment:
1- Who do not appeal to any other deity God [Alone], nor kill any soul whom God has forbidden [them to] except through [due process of] law, nor misbehave sexually. Anyone who does so will incur a penalty.
Torment will be doubled for him on Resurrection Day and he will remain disgraced forever in it , except for someone who repents and believes and acts in an honorable manner . God will replace their evil deeds with fine ones, since Gods is forgiving, Merciful.
Anyone who repents and acts hanrbly should turn to God in re repentance. (25:68-71)
2- Anyone who kills a believer deliberately will receive as his reward [a sentence] to live in Hell forever.(4:93)
3- So I have warned you (all) about a raging fire. Only the most wretched will roast in it, the one who rejects [the Message] and turns away.( 92: 14-16)
4- Those who disbelieve and reject our signs will become inhabitants of the Fire, to remain there. What an awful goal it is! (64:10)
5-Yet criminals will remain in Hell torment. (43:74)
The following verses also present the reasons leading to staying in Hell forever:
1- While those who disbelieve and reject our signs will become inmates of the fire , they shall remain in it! (2:39)
2-While those who reject My signs and act too haughty towards them will become inmates of the fire , they will remain there forever.(7:36)
3-Heavens gates will nor swing open for those who reject Our signs and feel too proud for them, nor will they enter the Garden until a camel can be led through the eye of a needled . Thus we reward criminals. (7:40)
4-Those who reject our signs and [the idea of] a meeting in the hereafter will [see] their works collapse. Will they not be rewarded for just what they have doing?( 7: 147)
5- We shall gradually bring those who reject our signs from a place they do not recognize. (7:182)
6- Those who deny [they will have] any meeting with God have already lost-out, so that when the How comes suddenly upon them , they will say: “ Have pity on us haw we neglected it!” “they will carry their burdens on their own backs. Is not whatever they bear something?” (6:31)
Sources :
Acquaintance with the Koran (Morteza Motahari)
The Noble Quran (English translation by T.B. Irving)