What does He who commits injustice is ever made more wretched than he who suffers it by Plato mean?

Answer 1

The general idea of Plato's quotation is that people who hold or act upon ill intent harm themselves far more than the other party. When one commits injustice, one does not suffer in the same way as those upon whom the injustice is inflicted, of course, but the suffering occurs all the same: it is internal rather than external, and the perpetrator may not even realize the change. The internal transformation through which one goes is subtle and gradual, but they continue to affect a person indefinitely. Time, then, is one factor that makes the injustice more wretched for the perpetrator than for the victim. Additionally, one action will most likely breed an appetite for even more injustice, and so the harmful cycle will continue.

A prime example is that of colonialism, specifically the effort made in King Leopold's Congo. Although millions of Congolese died, the men who perpetuated the violence and oppression were unrecognizable when they emerged from Africa: they were cruel, they were hard, they were hated by others and possibly by themselves. These men had to suffer the rest of their lives for every single person that they harmed, even if they denied that they were suffering.

As a final thought, Plato may have been invoking a religious element as well: those who commit injustice are all the more wretched because they will have to face the wrath of God when the final judgment day comes, for unlike the victims, they have no excuse of innocence or ignorance.