A slave becomes so by either selling himself or being sold by the court. In all cases, it is an economic necessity that forces the sale. Once enslaved, the person has many rights, and the owner has many responsibilities. He may not maltreat his slave, and he is held responsible to fully provide for him and his family.
Without going into detail, I will allow the following Talmudic quote to suffice: He who buys a slave has acquired a master for himself.
And yet, the Torah indicates that this institution, even in the humane and relatively dignified form of the Bible, is a negative one. Where do we see this? With regard to the ear-piercing ceremony.
The what?
You see, by Biblical law, all slaves are freed at the Sabbatical year. A slave may choose to NOT go free, and remain a slave. This makes sense, after all, since Bible slavery isn't a bad deal. The only responsibilities are to work for the master, and then he has to provide food, health, everything. Some may prefer that kind of life, especially if the master is a nice guy.
So when a slave chooses to remain so, he is taken to the court and they then pierce his ear. What is the meaning of this strange ceremony? Rashi, the Midieval Bible commentator, sees a rebuke to the slave in this: "The ear which heard 'You are all slaves to Me - God' yet has chosen a human master, deserves to be pierced."
In other words, God does not want us to be slaves. He wants us to be independent, responsible human beings. We must take care of our own world.
In stronger terms, what Rashi is telling us is that we are working for the Divine Master, at his business. What is his business? Fixing the world. He doesn't want us working for anyone with a lesser mission than that.
