This was originally written by Moses about 3,500 years ago. At the time, the common laws of all of the the lands included these things, things like slavery. People all over that area of the world (the Middle East) followed these basic laws and others.
The laws that Moses set up on the orders of God, were designed to be something that the people were familiar with, and were set up to form a theocracy type of government for Israel. It was also a government of family. The people of Israel at that time were very family minded, generally.
Throughout the centuries, people did as people do. Some of them followed the laws Moses set down. Some disobeyed. There is a strong common core of Jewish people who obey the laws Moses set down today. Note, there was/is no requirement to have slaves.
Thirty-five hundred years later, the basic laws of the world have changed so that slavery is formally outlawed. Yet, there are a lot of Arabs, especially in the Northwestern part of Africa, who still have slaves. Even the governments there condone it, but not officially, because of world views.
The word "slave" as written in many parts of the Old Testament was the word that we would use for "employee" or maybe "indentured servant." If a single man, today, had a female employee who lived at his house, he would not be required to marry her. In those ancient days, the honorable thing to do was to marry her... and it might be the honorable thing, now, if we were an honorable people.
If, back then, a female employee who was a wife got a different job, the husband might have to let her go as his employee. So, how do you treat a wife who was just an employee, but you were married to her (in name only) because it was the common law of the land and of the people? The laws Moses set up were a good way to assure that things were done fairly.
Just a reflection of and for the times as it was written during the times
Age of Aries
(1800 B.C. - 360 AD)
The preceding Age of Taurus was a very matriarchal and feminine Age in which fertility cults flourished, humanity began to master agriculture and survival needs, freeing up time and energy to pursue beauty and the creation of cities and civilizations. Some form of Bull worship emerged throughout most of the cultures on the planet, and can be found in various mythologies. Slowly things begin to change, the Bull was slain, and a new archetypal symbol and pattern begins to surface: The Ram of Aries.
The Age of Aries was an Age of incredible change. Astrologically and archetypally, Aries has to do with the development of identity via the ego, the “I am” that each of us carries within. As we assess the changes that evolved during this Age, remember that whenever a new archetypal pattern begins to download into our planetary chakra system, it begins to transform us at a first chakra, tribal level first. So a new quest for individuality became urgent around 1800 BC, rendering humanity with the impulse to find a "tribal ego" in our first attempts to break free of the more "earthy" psychic fusion of the Age of Taurus.
To identify with a singular, tribal affiliation and enact this, humans had to first consolidate their gods. Out of this impulse, monotheism was born. We see a single, dominant god emerge in most cultures--a god usually associated in some way with the Sun--and a shifting of the collective from matriarchal to patriarchal orientation in regard to issues of power and daily life. Tribal egos were born, making war a major theme of this Age–Aries is ruled by Mars, God of war, after all. (Aggressive assertion of the will is often required to break free from the past and become an individual, so perhaps this was a necessary step forward in our overall collective evolution.)
Harnessing the will became a focal point of humanity’s evolution and during this Age the "warrior of individuation" was born through many myths of the Mortal Hero. The Mortal Hero takes it upon himself to individuate from the feminine pull of the Mother (Earth-Taurus) and venture out to discover his identity through trials of courage and ego development (all Aries themes!)
During this Age, the Greeks gave us the likes of Homer, Hesiod, and Aeschylus with their solar myths of individuation, filled with mortal heroes like Achilles, Hercules, Jason (who sought the Golden Fleece!), Theseus (a bona-fide bull-slayer!) and Odysseus. Let’s also not forget Alexander the Great who, inspired by Homer, conquered most of the known world during this Age and was an embodiment of Aries’ drive, ambition, courage, will to power, pioneering spirit, and mythic vision.
To reintroduce the concept that each Astrological Age also manifests its opposite zodiacal sign as a balance (and key to the evolutionary phase at hand) let’s look at this concept shown clearly by our next mortal hero, Moses.
Moses is a Mortal Hero who is highly symbolic of the ego itself. Like Moses, the ego can liberate us from enslavement--to our past and our unconscious fusion to the mass psyche. It can birth an identity that brings us to the very edge of the “Promised Land” of the soul. But at the end of the journey, the ego cannot enter this Promised Land (a hint at the next Age, Pisces.) The Soul can indeed enter the ego, (a hint at the Age of Aquarius) and therein we find both the limitations, and ultimate fulfillment of ego development.
Still, Moses did much more than just liberate his people from Egypt. Like Alexander the Great, in his heroic quest, Moses was the Aries’ epitome of courage, loyalty, vision, determination, leadership, and faith in his unseen one god: Yahweh (Self). In condemning the worship of the golden calf (Taurus), he symbolically declared a new age had begun. An age that needed something to guide human ego development, something besides aggression and war – in which he gave the balance and polar opposite to Aries, the Libran law of the Ten Commandments. Interestingly, Moses also gave instructions in the building of the Ark of the Covenant that included a covering for the tabernacle made of ram’s skin, and a new altar with four horns at its corners.
As the Age of Aries progressed, and ego development began to move from tribal to individual, people became more cognizant of their own power and capacity to "reason" that perhaps war and aggression weren’t the best ways to engage with the development of individual identity. After all, what good was establishing an identity (Aries) if we couldn't relate it to others (Libra) without getting killed! We were in dire need of the archetypal energy of Libra, which deals in part with relating peacefully in a spirit of equanimity with each other.
Compare to other
cycles:
http://www.ohotto.com/features/astrological_ages_tour.asp