Some of the slavery in the law was also a form of penal punishment for criminal activity. Which in a lot of ways can be considered a far more efficient and effective means of dealing with thievery. If you steal something, you must pay back through servitude four times the value of what you stole, it is only fitting and logical. The thrust of the law would be placed in the hands of the people, enforced through the elder/judicial system. It (servitude) also benefited the culture rather than burdening it with a bloated and pointless prison system, which can actually become more cruel than a master/slave relationship, as a matter of fact if the Jews had truly believed and followed the greatest commandment as God had intended, indentured servitude would have been a phenominal opportunity to display this love of God to their servants. It would have been a massive oportunity for the Jewish people to demonstrate the light of God to the carnal worldly ways in which the wicked civilizations of old dealt with their slaves.
From so many practical points of view, this system would make so much sense in an agrarian society. Travis is right that we must be cautious when foisting our current cultural points of reference upon scripture, or even upon history. History is best understood in its own context.
In many ways...all men are slaves, the only difference is that some are called slaves and some are not. We are either a slave to the god of this world or we are to be a slave to Jesus Christ.
I once heard someone say that any man's greatest hope in life is to find a good master...
The greatest freedom from this worlds slave system is found in Galatians 6:14..."But God forbid that I should glory, save in the cross of our Lord Jesus Christ, by whom the world is crucified unto me, and I unto the world." A crucified slave does not care about anything but the will of his resurrected Lord...we are free from the tyranny's of this life.
Travis offered great insight also about what slavery was to be a picture of. This shows the wisdom of God and that all things work for the Good of those who love God and are called according to His purposes. Under grace, through faith the weapons of death are turned upon their intruding thieving master. The Christian holds within his bosom, via the Spirit...sense. Sense of all the foolishness of this life. The Christian thrives on hope, hope that God can make glorious something through what the Devil may intend as evil. (And in most ways, slavery has demonstrated the true color of the nature of the Devil, and the corresponding nature of the Devil's greatest compatriots...fallen men.)
God used the slavery of that day to make something beautiful.
Here is a tip for you for all your future scriptural study. Do not come to scripture with pre-conceived ideas. Come to the word of God bereft and naked of your personal prejudices. Come to the word of God as a child...or as a penitent sinner...beating your breast and begging for a propitiated mind. The word will thrive in you...it will free you from the clutches of the serpent. Wrath and doubting are the means where the devil will cast your eyes upon what he desires, which is always going to result in your hiding from God.
I know that may seem like a bold thing to say considering that we do not know one another, but doubting the veracity of the word of God is Satan's first...and most effective tool.
Presume that God is good. Good in his intentions...within this framework you will see that God always has bigger things in mind. With this approach in your tool belt as a bible student, you will do well.
God is, and He is a rewarder of those who diligently seek Him.