Now while it's true that slavery is, and always has been, morally wrong, this doesn't mean that slavery was always always morally wrong. There are many situations where the rules of the time and the culture of the society cause the absolute morality to be modified.
This means that while slave-holders were wrong to keep slaves 200 years ago, it wasn't wrong for people in ancient Israel to keep slaves.
This is because of any or all of the following reasons:
a) In that society slavery was simply the way things were done back then, so God "put up with it".
b) Slavery just wasn't that bad for Hebrew slaves, rather like
Club Med in fact.
c) Slavery might have been slightly harsher for non-Hebrew slaves
(minor things like beating them, selling them, and stealing their spouses and children),
but it kept them from sinning by giving them something useful to do.
d) It was based on nationality and ethnicity, not race, and so it
got the "moral thumbs up" from God.
e) It was really for the best, since the slavery provided shelter
and food for the slaves, and good labor for the owners.
Remember, none of these points have anything to do with moral relativism. This is true because there is no moral relativism in the Bible.
Following this same scheme, it is possible to resolve all the so-called "moral conflicts" in the Bible, all without ever saying the phrase "moral relativism".
So, when Bible attackers ask such mean-spirited questions as "If it wasn't wrong for the ancient Hebrews to own slaves, and now it is, didn't morality change?" you can safely say "No: morality didn't change, the situation and cultural context changed... in a way that doesn't involve any moral relativism of course."
All questions about the differences between the Biblical and the present morality of things like incest, adultery, racism, women's equality, child welfare, rape, murder, and genocide are also easily dismissed using this method.
Another method you may find useful is to claim the past behavior was seen as acceptable because a "greater good" was done. Thus, when God commanded people to murder and/or rape all the women and children of entire towns and nations, this was so those women and children wouldn't end up in hell, or be able to cause others to sin, or something else bad.
So murder, rape, and genocide were always wrong, but when God commanded people to do it back then, it wasn't moral relativism, so it was good. However, this argument only applies to the past: genocide, rape, and murder are really really wrong now, so do not try them now, no matter what greater good might come out of them!
You may want to re-read the previous steps if you have any questions on this step.
Step Eight