Deuteronomy 15:12

If thou buy an Hebrew servant, six years he shall serve: and in the seventh he shall go out free for nothing. If he came in by himself, he shall go out by himself: if he were married, then his wife shall go out with him. If his master have given him a wife, and she have born him sons or daughters; the wife and her children shall be her master's, and he shall go out by himself. And if the servant shall plainly say, I love my master, my wife, and my children; I will not go out free: Then his master shall bring him unto the judges; he shall also bring him to the door, or unto the door post; and his master shall bore his ear through with an awl; and he shall serve him for ever.

And if thy brother that dwelleth by thee be waxen poor, and be sold unto thee; thou shalt not compel him to serve as a bondservant: But as an hired servant, and as a sojourner, he shall be with thee, and shall serve thee unto the year of jubilee. And then shall he depart from thee, both he and his children with him, and shall return unto his own family, and unto the possession of his fathers shall he return.

At the end of every seven years thou shalt make a release.

At the end of seven years let ye go every man his brother an Hebrew, which hath been sold unto thee; and when he hath served thee six years, thou shalt let him go free from thee: but your fathers hearkened not unto me, neither inclined their ear.

And the servant abideth not in the house for ever: but the Son abideth ever.