וְעַבְדְּךָ֥ וַאֲמָתְךָ֖ אֲשֶׁ֣ר יִהְיוּ־לָ֑ךְ מֵאֵ֣ת הַגּוֹיִ֗ם אֲשֶׁר֙ סְבִיבֹ֣תֵיכֶ֔ם מֵהֶ֥ם תִּקְנ֖וּ עֶ֥בֶד וְאָמָֽה׃
And as for thy bondmen, and thy bondmaids, whom thou mayest have: of the nations that are round about you, of them shall ye buy bondmen and bondmaids.
Read kabbalistic (mystical) interpretation of Leviticus 25:44: and classical mystical sources.