I've been doing a bit more reading and I think, I can see another good reason related to our fallen state why everlasting punishment is just. If we as fallen beings need outside help to move from the kingdom of darkness to the kingdom of light how much more will we need it then? Or putting differently, if the grace of God is the only hope for salvation now what hope then for those who spurning Christ have been banished to the fiery lake? If an individual clings to their sin right to the moment of death what remedy will suddenly cure them from such folly in the world to come?
It's instructive at this point to consider the rich man described in Luke 16 who post-death is shown to be in hell. Have you ever stopped to reflect on the kind of assistance he asks for? This is what we read him saying
'Father Abraham, have pity on me and send Lazarus to dip the tip of his finger in water and cool my tongue, because I am in agony in this fire.'
Notice that all he wants is respite from his agony. He doesn't ask for help in turning to the Saviour.
I suppose all I'm saying is that continuing in sin now and dying in that state of sin offers no hope for someone suddenly turning to God in repentance in the afterlife, even if that were possible. In fact Scripture makes clear that the wicked are those who post-death continue rebelling against God even in the face of severe judgement. Thus for example we read in Revelation 16:9
They were seared by the intense heat and they cursed the name of God, who had control over these plagues, but they refused to repent and glorify him.
It seems to me therefore that everlasting punishment of the unrighteous in hell, is 'fair' in that the God's ongoing punishment in hell is not limited to just those sins committed whilst on earth, but will also be an expression of the on-going antipathy of the unrighteous towards God and their continuing sin. I wonder as well whether the phrase ‘gnashing of the teeth’ – a frequent expression of Jesus to describe the reprobate is an image of people grinding their teeth in rage or in helpless anger at God?
Put very simply the damned in hell persist in their sinning and therefore continue (in perpetuity) to incur God's wrath. The Apostle Paul was right all along:
For although they knew God, they neither glorified him as God nor gave thanks to him, but their thinking became futile and their foolish hearts were darkened.
Or to paraphrase the great Margaret Thatcher the people are not for turning