How is eternity in hell a fair punishment for sin?

An eternity of punishment for perhaps no more than seventy or eighty years of unbelief has many times been suggested as seeming quite unfair. There is a very good response to this false perception that God is inequitable. Consider our own system of justice.

If someone were convicted of having gone on a ten minute killing spree, about how much time would the law require them to spend in jail? An equal ten minutes? Obviously not. The punishment for any given crime addresses the quality of the crime, not, or not just, the quantitative aspect of the crime.

In the Bible's case, the key crime that sends anyone to hell is unbelief. Unbelief rejects God's ultimate sacrifice and is, in effect, equivalent of crucifying Jesus Christ. From a positional perspective, one's spirit is either on that cross crucified with Christ, or is outside of Christ, sided with the world that necessitated his death and bearing their own sin debt. So in a sense it is the infinite quality of Christ's life for which unbelief exacts a correspondingly infinite consequence. An infinitely long sentence for the infinitely bad crime.

By contrast, the reward of eternal life for even the shortest life lived in true belief has a far greater appearance of being unfair - unfair to God, that is. Without surprise, there is no objection to this side of the coin. Consider the thief who confessed his belief just moments before he died on a cross beside Christ. He received an infinite reward for...what? For simple, true belief. He received an infinitely good consequence for true belief, thanks only to the infinitely good quality of the life of Jesus Christ - the object of that belief.

When David sinned by committing adultery with Bathsheba and having Uriah murdered, he responded by saying something interesting: “Against you, you only, have I sinned and done what is evil in your sight…” (Psalm 51:4). David had sinned against Bathsheba and Uriah, how could David claim to have only sinned against God? David understood that all sin is ultimately against God. God is an eternal and infinite Being. As a result, all sin is worthy of an eternal punishment.

Yes, God loves us (John 3:16) “For God had such love for the world that he gave his only Son, so that whoever has faith in him may not come to destruction but have eternal life. and wants us to be saved”. God is also just and righteous – He cannot allow sin to go unpunished. That is why God sent Jesus Christ to pay the penalty for our sins. Jesus’ death was an infinite death, paying our infinite sin debt – so that we would not have to pay it in Hell for eternity (2 Corinthians 5:21). All we have to do is place our faith in Him and we are saved, forgiven, cleansed and promised an eternal home in heaven. God loved us so much to provide for our salvation. (If we reject His gift of eternal life, we will face the eternal consequences of that decision.)