Leviticus 25:44-46  New American Standard Bible

⁴⁴ As for your male and female slaves whom you may have—you may acquire male and female slaves from the pagan nations that are around you. ⁴⁵ 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. ⁴⁶ 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. ^(A)But in respect to your countrymen, the sons of Israel, you shall not rule with ^[a]severity over one another.