Leviticus 25:43-45

⁴³Thou shalt not rule over him with rigor, but shalt fear thy God.

⁴⁴And as for thy bondmen, and thy bondmaids, whom thou shalt have; of the nations that are round about you, of them shall ye buy bondmen and bondmaids.

⁴⁵Moreover of the children of the strangers that sojourn among you, of them shall ye buy, and of their families that are with you, which they have begotten in your land: and they shall be your possession.