Ariel Castro was to have spent a millennium in prison. That was his punishment after being found guilty of 937 criminal counts, including kidnapping, rape and murder. To be more exact, he was to serve life plus 1,000 years.

But after just about a month, he tied a bed sheet around his neck and cut short his life and his punishment.

That’s it. No more Ariel Castro. No more temporal punishment. After causing a living hell for the three girls he kidnapped and kept as sexual slaves for over a decade — girls who were continually raped, chained to a wall, locked in a dark room, fed one meal a day, regularly beaten, threatened with death, day after day, month after month, year after year — Castro made the ultimate escape.

Castro had pleaded guilty to the 937 criminal accounts so that he could avoid the death penalty, and then he imposed that penalty on himself.

We need to think about this. Deeply.

First, we need to think deeply about what it was like for the three young women, Amanda Berry, Georgina DeJesus and Michelle Knight. In 2002, Michelle was 21 when Castro abducted her. A third of her life would be spent in darkness, rape, violence, horror, stench, despair. Amanda and Georgina were thrust into Castro’s hell in 2003 and 2004, respectively. Amanda was 16, and Georgina only 14 years old. The morbid math: Amanda would spend a little over 40% of her life in hell, and Georgina would spend about 44%.

Time feels differently when you are having fun, going out with your friends, watching a good movie and laughing over a meal with your family. It goes fast.

But time crawls when you’re sitting in a dark room smelling your own urine and feces, chained to a wall, waiting for the horror of footsteps coming toward the door, being raped, giving birth in a plastic wading pool. Minutes are hours; hours are days; days are years; years are eternities.

How long did the three young women spend in Castro’s hell? You tell me.

The consideration of time brings up a second consideration: justice. The court sentencing Castro showed an admirable frustration in trying to render a just punishment. A mere lifetime of sitting in a prison cell — a well-lit cell, a cell with a real toilet, a cell where Castro would not be chained to the wall or raped or beaten, a cell where he could watch TV, read and take his three meals a day — was not a punishment that fit the enormity of the crime.

The court therefore added 1,000 years to his lifetime as if to say, “Ariel Castro, for what you did, you should be held behind bars for a span of time equal to that which passed between the kingship of David and the birth of Christ, a time greater than the span between the Battle of Hastings and this very day of your sentencing, a period of punishment almost four times the age of this country under whose laws we now pronounce this verdict.”

Yet, justice isn’t just a matter of time. Justice means giving what is due. Justice means that Ariel Castro should be made to experience, in himself, the full horror of what he did. Not just a sip of it, but the whole cup. Only then would he be able to say, “I see now what I have done. I see the hell that I caused these three women. I have now drunk as deeply as they did from the bitterest depths of their despair, pain, humiliation and darkness, and I am as deeply sorry.”

That’s repentance. And that’s what true justice, with mercy at its heart, aims to bring about in the one punished.

But just as the amount of time due Castro for his punishment exceeds that which a merely human court can give, so also does the depth of punishment.

If that weren’t bad enough, Castro wasn’t truly sorry. Of course, he said he was sorry, sort of, in a rambling 20-minute speech. But he also said he wasn’t really to blame because he was “a victim of sex acts when I was a child,” and so, “I’m not a monster. I’m sick,” and “I am addicted to porn,” and “I’ve been a musician for a long time 20, 25 years. ... I’m a happy person inside,” and “I’m not a violent person,” and “Most of the sex that went on within the house was consensual. These allegations [of my being] forceful on them is totally wrong. There was times they would ask me for sex. Many times,” and “I hope they can find in their hearts to forgive me because we had a lot of harmony going on in that home.”

That’s the Castro who hanged himself, a man without true remorse.

That’s why there is hell.

If there were no hell — no place wherein a moral monster like Castro undergoes the punishment he deserves for as long as he deserves it — then, at least in this case, there would be no justice. But human beings cannot live in a universe without justice, and so they cannot live in a universe without hell as long as there are moral monsters like Castro who escape the punishment they deserve.

Not convinced? Imagine your sense of moral outrage at the violation of justice if the court had actually sentenced Castro to one month in prison.

This is not an argument about revenge. To experience the hell he caused would be — if undertaken in the right spirit — the very thing that could bring Castro to true repentance. He would know what he had done, and that is what he would be truly, deeply sorry for.

Hell is the mercy of justice aimed at bringing about true repentance but refused by the recipient. It is the proper punishment without the proper response.

At the finale to his final ramble, Castro did say, “I’m sorry for everything. I know true Jugment Day is when God comes and judges me. I’ve been reading the Bible. I’ve been asking for forgiveness. … Please find it in your hearts to forgive me.”

So it really may be that Ariel Castro is not in hell. But even if he was truly sorry, that should only be the beginning of his punishment, not just another way (like hanging himself) to avoid it. For his sake, he must still experience the hell he caused, or he isn’t sorry for what really happened.

That’s why there is purgatory.

I believe it was St. Thomas Aquinas who said, if I may paraphrase it, that there is no difference between the fires of hell and the fires of purgatory. The difference lies in how the fires are received. In purgatory, the souls feel the punishment as the redemptive cleansing they desire with all their hearts to undergo. In hell, they feel only the pain.

Benjamin Wiker is a faculty associate of Franciscan University’s Veritas Center for Ethics in Public Life and a visiting associate professor at Franciscan University. He is the author of 12 books, the most recent being How To Think about GOD on a Plane. His website is benjaminwiker.com.