Rashi on Deuteronomy 28:69/רש"י על דברים כ״ח:ס״ט

1לכרת את בני ישראל [THE COVENANT WHICH THE LORD COMMANDED …] TO MAKE WITH THE CHILDREN OF ISRAEL — that they will take upon themselves the observance of the Torah under an imprecation and oath (cf. Deuteronomy 29:11).

2מלבד הברית BESIDES THE COVENANT — i.e. the curses in Torath Cohanim (Leviticus 26:14 ff.) which were spoken at Sinai (Horeb).