Leviticus 25:45-49

You may also acquire them from the sons of the foreign residents who reside among you, and from their families who are with you, whom they will have produced in your land; they also may become your possession.

You may also pass them on as an inheritance to your sons after you, to receive as a possession; you can use them as permanent slaves. But in respect to your countrymen, the sons of Israel, you shall not rule with severity over one another. Of Redeeming a Person Who Is Poor

‘Now if the means of a stranger or of a foreign resident with you becomes sufficient, and a countryman of yours becomes poor in relation to him and sells himself to a stranger who is residing with you, or to the descendants of a stranger’s family,

then he shall have redemption right after he has been sold. One of his brothers may redeem him,

or his uncle, or his uncle’s son may redeem him, or one of his blood relatives from his family may redeem him; or if he prospers, he may redeem himself.