Leviticus 25:41-51

41 and he shall go out in the release, and his children with him; and he shall go to his family, he shall hasten back to his patrimony.
42 Because these are my servants, whom I brought out of the land of Egypt; such an one shall not be sold as a servant.
43 Thou shalt not oppress him with labour, and shalt fear the Lord thy God.
44 And whatever number of men-servants and maid-servants thou shalt have, thou shalt purchase male and female servants from the nations that are round about thee.
45 And of the sons of the sojourners that are among you, of these ye shall buy and of their relations, all that shall be in your lands; let them be to you for a possession.
46 And ye shall distribute them to your children after you, and they shall be to you permanent possessions for ever: but of your brethren the children of Israel, one shall not oppress his brother in labours.
47 And if a stranger or sojourner with thee wax rich, and thy brother in distress be sold to the stranger or the sojourner that is with thee, or to a proselyte by extraction;
48 after he is sold to him there shall be redemption for him, one of his brethren shall redeem him.
49 A brother of his father, or a son of his father's brother shall redeem him; or let one of his near kin of his tribe redeem him, and if he should be rich and redeem himself,
50 then shall he calculate with his purchaser from the year that he sold himself to him until the year of release: and the money of his purchase shall be as that of a hireling, he shall be with him from year to year.
51 And if any have a greater number of years , according to these he shall pay his ransom out of his purchase-money.

The Brenton translation of the Septuagint is in the public domain.