So you are saying that ordinary standards of morality didn't apply before Jesus?
The discussion began with the assertion that things in the Bible didn't change or become obsolete over time. Perhaps I am just too dense to "get it", but the morality of owning another human is a pretty big bite to swallow. Not to mention asserting that it is OK to beat another human being to the point where it takes two days for him to get up. Or that it is OK to have slaves, provided they come from another country.
I accept the fact that religious ideas evolve along with society in general, but I reject the idea that the underlying nature of morality changes.
The ONLY way that works is if being an Athenian slave is so far above being a Scythian for whatever combination of reasons, that the proposition is a no-brainer.
Give up trying to judge ancient people by your own standard of morality; it doesn't work.