Evil could not exist apart from evildoers, for there is no one to carry it out apart from them. Without the practicer of immorality, there is only the logical possibility of a given being committing evil. There is thus only one way to truly, completely eradicate evil: purge the incorrigible evildoer from existence. Of course, this could only be achieved by inflicting a state of true death on them, and for it to be true death, they cannot exist as either an unembodied or embodied consciousness in some eternal afterlife. Forcing someone to avoid evil is impossible for a being of particular metaphysical limitations, as with one person being incapable of making another living, conscious person stop evil thoughts—yes, they could render them unconscious or kill them, but this is not at all the same as willing that another person cease their evil and making them mentally comply. Otherwise, such an ability would be reserved for some being of superhuman power, like a deity who could override another entity's free will if it chose to so that they still live and yet no longer engage in certain thoughts or behaviors.
In Deuteronomy, there is repeated emphasis on how capital punishment, exclusively in the cases which and with the methods which make it righteous (for anything else could only be unjust), purges evil from a community. See Deuteronomy 13:5, 17:7, 12, 19:13, 18-19, 21:20-21, 22:21-22, 24, and 24:7 for instances of this. How can one purge evil from among a group? Again, this could only be accomplished in the strictest sense by the death of the wrongdoer. In this way, there is no possibility for the sinner to be expelled or flee so that they bring continued evil elsewhere. Not even exile accomplishes this. No, if they are dead, their sin perishes too. Certainly, not every Biblical sin deserves the premature death of execution carried out by other humans despite how all sin deserves death (Ezekiel 18:4, 20, Romans 1:32, 6:23). The Bible clarifies which sins merit such a human response. However, not a single sin of any severity could deserve eternal torture, more importantly. The Bible agrees, condemning such treatment by virtue of declaring anything past certain thresholds inherently evil (Deuteronomy 25:1-3, Luke 12:47-48). It would crucially be true independent of Christianity, by strict logical necessity, that infinite torture for finite sins, no matter the degree of torture or the sins being punished, could only be unjust because of infinite disproportionality—the greatest category of evil.
Hell is just, and so hell does not involve eternal torture. It is where people are killed for their sins unless they repent (Matthew 10:28, Psalm 37:20, Romans 2:7-8, and many more). Death in hell is the ultimate capital punishment in its effects. People, as Jesus says in Matthew 10, can kill the body but not the soul. Once the wicked soul is restored from the unconsciousness of Sheol (Ecclesiastes 9:5-10) at the resurrection (Daniel 12:2), God can then kill body and mind once and for all, with no opportunity for another resurrection. Only the righteous will have eternal life. It is logically impossible for someone to be given what they already have. A person can be given wealth when they already have wealth, but a belonging they already possess cannot be given to them. Someone either has eternal life or they do not. Only if they do not can they receive it as a gift from God. If only the righteous live without end, however, then evil really will be no more. There is also no other way that the old order corrupted by sin can pass away so that there is no more evil or death (Revelation 21:1-4).
Evil truly would then have been purged from creation; the enemies of God, of righteousness, are destroyed in the second death (Revelation 20:15) so that death itself never again occurs, death itself being the last enemy of God to be destroyed (1 Corinthians 15:26), which requires that the others have already been banished from existence. There is no more evil and no more deserved death due to evil because none are left who practice it. Instead, the lifeless bodies of those who unrepentantly opposed God are seen by the righteous (Isaiah 66:22-24). Execution in hell is the grand, universal capital punishment for everyone who persistently refuses the truth. In perishing (John 3:16, 2 Thessalonians 2:10), they no longer exist in order to do evil. This is justice and it also has the effect of cleansing reality from the presence of evildoers. Sin gives birth to death (James 1:13), the latter of which is the wages, the just earnings, of the former (Romans 6:23). Yahweh is not a utilitarian. Annihilation of sinners in hell is not justice simply because of the positive consequence of there literally being no more sin in existence any more than eternal torture is just because it could inspire dread to the point of deterring all sin. Any alternative to annihilation, though, would involve the permanent existence of evildoers and thus of evil.
