This has less to do with the historical truth of the Exodus and more the Israelite society allegedly being founded by ex-slaves. After whatever event freed the Israelites from Egyptian rule, how was slavery perceived in the society and amongst its people? How was it treated legally?
EDIT: Just to be clear, not a historian, but I’ve been reading this book for the past ten years, I think I know a little bit about it.
The Law actually says a lot about slaves and servants and how you were to treat them. How well they followed it or if they followed it all is questionable whether you believe the Bible (That’s a heavy theme of the Old Testament) or not but we can look at what they thought they were supposed to do.
Among fellow Israelites the law was explicit about keeping one another out of poverty, helping the poor, forgiving debts Ect. But not everyone cooperates. So if you could not afford to pay a debt, pay for your land, pay for a dowry, or if you couldn’t even take care of yourself, you could sell yourself, or your children and become a servant.
But this was not permanent. The law gave you two outs. You could work for seven years then you were free to go. If you married while in service and had kids, the owner kept those. And if you were Female, you had to marry into the family, if you could. But other then that, you were free. You could even go back to your own land or your husbands land if you were working off a Dowry.
Interesting though if you didn’t want to leave, you could become an Indentured servant, from Exodus 25.
“But if the servant declares, ‘I love my master and my wife and children and do not want to go free,’ then his master must take him before the judges. He shall take him to the door or the doorpost and pierce his ear with an awl. Then he will be his servant for life.“
Basically if you treated your slaves well, they could stay on and become basically a family member. It’s was a good incentive to be nice to slaves. (And there were laws in place to prevent people from like forcing slaves into indentured servitude without consent but that’s another story)
The other way to be free was called the year of Jubilee. The idea was that every fifty years, all debts just stopped. If you sold land to someone, you got it back. If you owed someone money, you were covered. And if you were a Israelite slave, you were free. Period. And as cool as it sounds (If completely unpractical for a more advanced civilization) I can say for certainly, I doubt this was ever observed due to Ocupation and quarreling before the exile. And afterwards, land was fairly scarce.
Foreigners weren’t quite as lucky. If someone came to live in your land peacefully, you weren’t allowed to enslave them. The law said that you should incorporate Foreigners into your land and basically make them Israelites. People you were fighting though were fair game. Though most of the time, the law said kill everyone and take none for slaves. Like the invasion of the promised land, and they didn’t want the natives to breed with the Israelites so they didn’t turn to idols. The Old Testament acknowledges this didn’t happen basically at all. And Foreign slaves were not under the seven years rule, I don’t believe. Luckly the law was pretty lax about becoming an Israelites. Basically be circumcised and respect Passover. So a foreign slave could become an Israelite and become free by extension.
Treatment of slaves was pretty good according to the law. You were to respect slaves as people, feed and give them space, and refrain from sexual relations. Indetured servants were to be treated as family. And punishment for mistreating slaves ran from heavty fines to freedom for the slave.
I’ve been mostly pulling from Leviticus, Exodus, Joshua, and the all important, Spurgeon’s commentaries.