Leviticus 25:45-47

⁴⁵Moreover of the children of them that dwell as sojourners with you, of them may ye buy, and of their family that is with you, which they beget in your land, and they shall be your possession.

⁴⁶And ye shall leave them as an inheritance to your children after you, to inherit them as a possession: these may ye make your bondmen for ever; but as for your brethren, the children of Israel, ye shall not rule over one another with rigour.

⁴⁷And if a stranger or sojourner become wealthy beside thee, and thy brother beside him grow poor, and sell himself unto the stranger, who is settled by thee, or to a scion of the stranger's family,