Leviticus 25:53-55

⁵³As a laborer hired from year to year shall he be with him; he shall not rule over him with rigor before thy eyes.

⁵⁴And if he be not redeemed by one of these means: then shall he go out in the year of the jubilee, both he, and his children with him.

⁵⁵For unto me are the children of Israel servants, my servants are they, whom I have brought forth out of the land of Egypt: I am the Eternal your God.