@Big Dog
That's an interesting question: why are there terms like "slave" but also "king"?
A common answer is that the NT just reflects the socio-economic conditions of the time. But this is seen by many as an insufficient answer. What is missing is any significant criticism, for example of slavery in particular. Paul's letter to Philomena does deal with the realities of "slavery", but its solution is not to criticize slavery as an institution, but to overcome the conflict that arises from this phenomenon by Christianity overcoming the conflicts of people that arise from human social roles/states as slave or master, male or female.
This is indeed a highly effective solution, but only within Christianity and only if people accept it: Paul could only appeal to Philomena. To finish: From the legal practice preserved for us in Egyptian papyri of the Roman era, it can be traced that the master, often entrusted a slave with some business dealings. Commercial contracts were standardized and contained clauses stating what damages could be claimed if the terms of the contract were not fulfilled. Typically the sale of, for example, a donkey. The donkey was described, and a sale price was set. The buyer undertook to inspect the donkey and not to claim damages if the donkey died or ran away on the way home after the sale. If in such a case the buyer demanded something back, the seller was entitled to a full refund and the buyer was to hand over the same amount to the municipal treasury as a fine...
In the hypothetical case where Filomenus had entrusted his slave Onesimus with some business and Onesimus had run away, Onesimus might have put his master in a very precarious situation: Filomenus might have been forced to return some money and might have been fined for the thwarted business, he might have been subjected to execution on the property, or he and his whole family might have been thrown into prison until he, or some guarantor, could buy him out of prison. All these things were possible...
Thus, a master could easily become a "slave" just because a slave failed to perform a task.
Paul's appeal to Philomena to forgive Onesimus because he had become a Christian could have been a great challenge to Philomena's character: a runaway slave could have been quite deservedly punished, and very brutally, because the slave's actions could have put the master or even his family in vital danger...
Again: while this explains the Christian attitude towards slavery, it in no way says that slavery is to end.
Why is there no criticism of this or any other contemporary institution?
I answer this again with an example from the Egyptian papyri of the Roman period. There are several papyri where it is written that XY found an infant, a girl or a boy, in a dunghill (really literally: dunghill, garbage dump), and gives this infant to a nursing mother QW, for a fee, for 2 years, to nurse this "little body" (the texts use the term "little body", they don't talk about the child at all), and then return it to XY. The milkmaid undertook to do this and that.
The papyri survive regarding disputes when the "foundling" died and the grantor, oak claimed the nursemaid's child, thinking this was the foundling...
There is no mention in the NT-text of the practice of abandoned children (if no one found them, they died - cf Egypt and the birth of Moses) or someone found them and gave them up for rearing and then made slaves of them. It may not have been the practice in 1st century Palestine, but since Christianity spread very soon, then they must have been confronted with the issue. What about the children left on the dung heap? How many to save? Shouldn't that be outlawed?
So there were more of these burning questions and some were not even mentioned.
The only answer I have so far is that Christianity at the time was, shall we say, a sect of a few thousand people who did not seek any "political" influence to change any social phenomenon. Question: How do you as a church feel about abortion or homosexuality or LGBT? assumes that the church has some social influence. That it has enough power to change something or at least to influence public opinion in (dis)favor of something.
This power influence, this ambition, is - in my opinion - completely alien to early Christians. They changed themselves and, at most, their family members. They were not indifferent to other people's suffering (see Samaritan), but this only confirms the above point that love or mercy ("the poor you will always have around you") was connected to their person and situation. Now and therefore. I'm not fighting against slavery being eventually replaced by feudalism or capitalism or a communist gulag.
The system was overcome (say: eliminated) by love and mercy primarily within the Christian group, not by cutting something off the attacker with a sword (already a severed ear was a problem...).
