Leviticus 25:45 in the King James Version
Moreover of the children of the strangers that do sojourn among you, of them shall ye buy, and of their families that are with you, which they begat in your land: and they shall be your possession.
Context
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.
45 Moreover, 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.
46 You 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.