45And also of the children of the strangers that sojourn with you, of them may ye buy, and of their families that are with you, which they have begotten in your land; and they shall remain to you as a possession.
46And ye may transfer them as an inheritance for your children after you, to inherit them for a possession; you may hold them to service for ever; but over your brethren the children of Israel, one over the other, ye shall not rule with rigor.
47And if a stranger or sojourner wax rich near thee, and thy brother become poor near him, and he sell himself unto the sojourning stranger near thee, or to a descendant of a stranger's family:
Leviticus 25
Leviticus 25:45-47