1) On the whole Jesus himself is not shocked by the existence of hell, but by the hardness of people’s hearts. As I already suggested, that may tell us that we need to wrestle much more diligently with how God looks at sin, and the degree and degradation and moral offensiveness of the sin that he sees.
2) There is no hint in the Bible that there is any repentance in hell. There may be a cry for relief, or a plea, but there is no hint of repentance (Lk. 16:19-31). Perhaps, then, we should think of hell as a place where people continue to rebel, continue to insist on their own way, continue societal structures of prejudice and hate, continue to defy the living God. And as they continue to defy God, so he continues to punish them. And the cycle goes on and on.
3) We must always remember that the Bible does not present us with a God who chances upon neutral men and women and arbitrarily consigns some to heaven and some to hell. He takes guilty men and women, all of whom deserve his wrath, and in his great mercy and love he saves vast numbers of them. Had he saved only one, it would have been an act of grace; that he saves a vast host affirms still more unmistakably the uncharted riches of that grace.
4) Heaven would surely be hell to those who do not enjoy and desire the blessing of the unshielded presence of God.
5) The God of the Bible is not unmoved by our suffering. He is slow to anger, abundant in mercy. Jesus, after saying “woes” to the religious hypocrites of his day, ends up weeping over the city of Jerusalem (Mt. 23). Though the Bible speaks plainly [about hell], and sometimes in fury, it never does so without tears. And Christians can never forget that they too, like the rest, are by nature objects of wrath. They never warn others about the wrath of God from a position of intrinsic superiority, but from the broken experience and the relief of redemption they want to share.
These excellent quotes (edited for length) are found in D. A. Carson, How Long O Lord? p. 90-93.