Exodus 21:2-6

²“If you buy a Hebrew slave, he shall serve for six years; but on the seventh he shall go out as a free man without payment. ³If he comes alone, he shall go out alone; if he is the husband of a wife, then his wife shall go out with him. ⁴If his master gives him a wife, and she bears him sons or daughters, the wife and her children shall belong to her master, and he shall go out alone. ⁵But if the slave plainly says, ‘I love my master, my wife and my children; I will not go out as a free man,’ ⁶then his master shall bring him to God, then he shall bring him to the door or the doorpost. And his master shall pierce his ear with an awl; and he shall serve him permanently.