Wondering about not having to die anymore
When the man who has been mentioned here will peep into Jahannam to have a look at his disbelieving acquaintance, it has been mentioned that the same man will be so delighted with the blessings of Jannah that he will exclaim: "Is it that we do not have to die anymore?" It does not mean that he will not be certain of the eternal life of Jannah. Instead, it is like the case of a person who achieves the highest degree of happiness. Such a person would occasionally break into exclamations that show as if he does not believe his eyes on having received such enormous blessings. These remarks are of the same nature.
Towards the end, the noble Qur'an turns our attention to the essential lesson embedded in this event and says: لِمِثْلِ هَـٰذَا فَلْيَعْمَلِ الْعَامِلُونَ which means 'For this kind (of achievement), all workers must work.'