Leviticus 25:46

44“‘As for your male and your female slaves, whom you may have from the nations that are around you, from them you may buy male and female slaves.

45Moreover, of the children of the aliens who live among you, of them you may buy, and of their families who are with you, which they have conceived in your land; and they will be your property.

46You may make them an inheritance for your children after you, to hold for a possession. Of them you may take your slaves forever, but over your brothers the children of Israel you shall not rule, one over another, with harshness.

47“‘If an alien or temporary resident with you becomes rich, and your brother beside him has grown poor, and sells himself to the stranger or foreigner living among you, or to a member of the stranger’s family,

48after he is sold he may be redeemed. One of his brothers may redeem him;