Why is hell going to be so awful for those who go there?
Hell is so awful because those who go there will realize they chose it themselves. Their sins were already atoned for through Christ's death, burial, and resurrection, yet they did not appropriate that atonement. They will understand that a fair God provided the payment, so their eternal separation is not God's fault but their own rejection.
Les explains that at Christ's resurrection more power was exercised out of the Godhead than in anything else God ever did, because through it He totally defeated all powers of Satan and settled the sin debt for every human being. Les stresses that the sins of every human being have already been atoned for. Therefore, when people go to an eternal hell, it will not be God's fault, since they already received the atonement but did not capitalize on or appropriate it. That is what makes hell so awful: they will suddenly wake up and say, "I'm here because I chose to be." They will know it is not because an unfair God sent them there, but because a fair God declared those sins paid for at the death, burial, and resurrection of Christ. Les notes that it took all the power God had at His disposal to raise Christ from the dead, and that this is the very benchmark of our salvation experience.