So let me examine a couple of points you wish to contradict:
- The Bible says to treat slaves decently
- God – the purported all-powerful creator and determiner of right and wrong – simply couldn’t outright abolish slavery.
If we look at what we Christians regard as the ultimate moral authority - the teachings of Christ and his apostles - then, yes, the New Testament clearly says to treat slaves decently. That really can’t be denied.
What many secularists take issue with is why Jesus supposedly didn’t “explicitly” abolish or condemn slavery.
This brings up a question I have never heard adequately answered - if you think Jesus had authority as a moral teacher (whether you believe He was Divine or not), why weren’t you at Mass with me this Sunday, partaking of the Eucharist?
Clearly, Jesus commanded many things - we are not to look at women with lust in our hearts, we are to follow the Commandments, we are to treat the least among us as we would treat Him, we are not to gossip, we are to give alms every time we see that homeless guy under the overpass, and we are to consume His transubstantiated body and blood in the form of the Eucharist and enter into a communion with all your fellows. Do you (or anyone you know) do all those things?
(I’m not saying I do consistently, by the way, or that I am any better than you - I’m a sinner, as are we all.)
Even if we set aside all those other messy teachings about His Body and the Blood which you probably don’t believe - if you, or anyone else, occupying a position of, as you said, “love, compassion, sympathy and honesty” can’t consistently do all those things…what makes you think everyone would obey His rule regarding slavery?
Some would, clearly, just on the basis of His command. But not all.
This is often a fundamental failing in the arguments of some (not all) atheists - the belief that to
know is all we need to
do. That all we need is to have the right path pointed out to us, and we will choose it and then become better persons. St. Paul was a far better judge of human nature - he recognized that we know the right thing to do, but still fail to do it: “For that which I do I know not: for not what I would, that do I practise; but what I hate, that I do.”
(The same failing to understand human nature occurs in the atheist argument that “If God wanted us to be good, why doesn’t he just appear over Times Square?”, or “If God wanted all people to follow him, why did he appear in bronze age Jerusalem instead of in modern times?” Again, we have shown no propensity as a species to consistently act with love, compassion, sympathy, and honesty…even when we know we should. What difference would a divine light show over Times Square make?)
Clearly, Jesus disliked slavery.
Clearly also, he did explicitly condemn it.
Clearly also, his padawans condemned it. Both St. Paul and St. John did explicitly condemn it, and they weren’t known for freelancing their ideas. The times Jesus spent before his death and after it were obviously spent discussing Important Things, and the fact that both these key figures condemned slavery (although neither were themselves slaves) is the best evidence that an anti-slavery position was part of the Deposit of Faith left to His followers.
Clearly, also, the Early Fathers of the Church and the Saints condemned it, passing on the Deposit of Faith.
(I realize many atheists aren’t comfortable with the Catholic doctrine of the Deposit of Faith, as many are as legalistic and literalistic about scripture as the most died in the wool Young Earth Creationist. Many feel more comfortable if all they have to argue is what is available to them is a text, and they can argue that if “it wasn’t written down, it didn’t happen!” In many cases, it’s because they were formerly in a sola scriptura faith tradition and they are more comfortable arguing when they have a known doctrine to dispute. They often feel the Deposit of Faith gives too much wiggle room to their opponents in a debate, or discussion. But that’s how Catholicism works, and always has.)
So: Jesus wants to end the evil of slavery. Just condemning it outright does not work, anymore than condemning adultery does. He has to do something far harder than changing minds - he has to change hardened hearts - both the slavers, and perhaps even more difficult, the slaves, who are rightly angry at the system that holds them, and the people who have claimed ownership of them. How does He do it, when other slave revolts, such as that of Spartacus, left thousands dead and crucified and the same bloody system still in place?
Jesus doesn’t work through military overthrow or revolution. He has another secret weapon.
His own Body and Blood.