וְכָל־עֶ֥בֶד אִ֖ישׁ מִקְנַת־כָּ֑סֶף וּמַלְתָּ֣ה אֹת֔וֹ אָ֖ז יֹ֥אכַל בּֽוֹ׃
but every man’s servant that is bought for money, when thou hast circumcised him, then shall he eat thereof.
Read kabbalistic (mystical) interpretation of Exodus 12:44: and classical mystical sources.