Let's not forget Exodus 21 2-6 where it tells you how to trick a person that has signed up for a seven year stint as an indentured servant into being a slave for life:
2If you buy a Hebrew servant, he is to serve you for six years. But in the seventh year, he shall go free without paying anything.
3If he arrived alone, he is to leave alone; if he arrived with a wife, she is to leave with him.
4If his master gives him a wife and she bears him sons or daughters, the woman and her children shall belong to her master, and only the man shall go free.
5But if the servant declares, ‘I love my master and my wife and children; I do not want to go free,’
6then his master is to bring him before the judges.
a And he shall take him to the door or doorpost and pierce his ear with an awl. Then he shall serve his master for life.