Whereas for those who are unbelievers there will be the Fire of Hell. They will not be killed off so that they die In other words, Allah is saying they cannot die. its punishment will not be lightened for them. They are in a constant state of torment. That is how We repay every thankless man. They will scream out, O Lord, let us out, let us do something purer than what we have done. In other words, they will beg to be sent back to the world. They will ask to be able to exhibit pure behavior. Allah says, Did We not let you live long enough for anyone who was going to pay heed to pay heed? In other words, Allah asks whether they had not been given sufficient time.