There was a song we used to sing about God piercing our ears as a mark of willingly becoming a bondslave, according to the process laid out in Deuteronomy 15. At the time, I was going through a heated debate with my parents, who felt I was not old enough for pierced ears, so I really liked that song, and sang it defiantly. I did not understand it then, but that particular part of the Torah was not about jewellry. The meaning of this ear-piercing ritual that God outlines in the law is much more profound than I could possibly have imagined.
The instructions for making a regular slave into a bondslave are laid out twice in the Torah: Exodus 21, and Deuteronomy 15. As a rabbi once pointed out to me, it is highly interesting that right after the Ten Commandments, when God launches into his law, this the very first thing he says: