Rashi on Leviticus 25:55/רש"י על ויקרא כ״ה:נ״ה

1כי לי מי ישראל עבדים FOR UNTO ME THE CHILDREN OF ISRAEL ARE SERVANTS — My document (deed of purchase) is of an earlier date (cf. Rashi on v. 42).

2אני ה׳ אלהיכם I AM THE LORD YOUR GOD — Whosoever enslaves thee (the Israelites) on earth enslaves, as it were, Him in Heaven (Sifra, Behar, Chapter 9 4).