Certainly Christian societies appealed to Christian virtue when working to abolish slavery in the 19th century. As Pope Francis recently taught, there was development of doctrine at play here. The Gospel contains the fullness of truth but the Church’s understanding of the Gospel has deepened over time.
While there were Christians who fought to abolish slavery (both Catholic and non-Catholic) they had to combat the Church’s outright endorsement of slavery (as I detailed above) and the words of God himself giving explicit details on how to increase slavery in the world. You say the Gospel contains the fullness of truth, as though it shows God against slavery, but there is not a single word in the Gospel saying slavery is wrong. To call it a development of doctrine or a fulfilling of truth would suggest that Christianity was at least partway against slavery, but without a doubt that is simply untrue. Doctrine has flipped 180 degrees on slavery. That’s not a “development”. That’s an overturning. The abolishment of slavery owes FAR more to the Elightenment than any church that has been on the side of slavery for NINETEEN centuries (95% of its existence).
I don’t believe that God commanded or instituted slavery in a culture that previously had no slavery. I believe slavery was already present and accepted and God met His people where they were. I do accept the Exodus, but not necessarily the received text as an exact historical account of how things went down.
The Catechism says that all scripture is true, whether literally or figuratively. So even if you say God didn’t literally speak to his people on these matters, it does mean that if scripture says God is for something then he is for something.
If you’re saying that the Exodus was true, but that they were practicing slavery… then how is that possible? Slaves don’t have slaves. God introducing his slavery rules to the Hebrews in the desert means that they had no opportunity to obtain slaves between crossing the Red Sea to the speech starting in Exodus 20.
It’s important to note that Exodus 21, which contains a large portion of God’s rules and regulations on being a slaveowner is in the same monologue where God allegedly first gave the 10 Commmandments. If you want to discount one part of it then you have to allow the other parts to be discounted as well.
It’s true that there is no verse that specifically says that God hates slavery, but you often find the general sentiment of protecting the weak and the poor…slavery was never an ideal. It was as always a result of sin… as is divorce. (Though you’re right that they’re “different beasts”).
You can’t have numerous passages of God specifically outlieing how to do all sorts of utterly cruel things to slaves (including God in Leviticus on purchasing slaves from neighboring nations) then play it off as God not wanting his people to do the
very things he told them they could do. It simply doesn’t add up. You can discard the specific words of God because they would paint him in an awful light.