Leviticus 25:39-45

39“If your brother becomes poor beside you and sells himself to you, you shall not make him serve as a slave: 40he shall be with you as a hired worker and as a sojourner. He shall serve with you until the year of the jubilee. 41Then he shall go out from you, he and his children with him, and go back to his own clan and return to the possession of his fathers. 42For they are my servants, whom I brought out of the land of Egypt; they shall not be sold as slaves. 43You shall not rule over him ruthlessly but shall fear your God. 44As for your male and female slaves whom you may have: you may buy male and female slaves from among the nations that are around you. 45You may also buy from among the strangers who sojourn with you and their clans that are with you, who have been born in your land, and they may be your property.