Let me also say that if you think all these social classes are codified, you must be reading only every other verse of Colossians 3. The full picture is: treat each other as equals, but without offending the culture and thereby disturbing the peace and painting a negative picture of Christians in outsiders' minds. And turn the other cheek to corrupt authority, and render unto Ceasar. That doesn't make their authority rightful, nor their culture, rather you are pleasing all people in all things whenever it is not wrong to do so, both to be good to them and to hopefully save them.

Don't even try using Old Testament laws. They are a compromise with Israel. Jewish law allows divorce, but it is still wrong. Likewise it may also allow certain forms of slavery and revenge that fits the crime, but that does not mean those things are right either. Not only that, but according to the prophets many of those laws were both not good and unkeepable in the first place, and the writings were later corrupted by scribes on top of that. That explains why all the patriarchs are completely unaware of so many laws, because they were actually forged after their time. It also explains why the books of Moses and "history" books have such different ethics than the New Testament, prophets, and wisdom writings.