לְעָבְרְךָ֗ בִּבְרִ֛ית יְהוָ֥ה אֱלֹהֶ֖יךָ וּבְאָלָת֑וֹ אֲשֶׁר֙ יְהוָ֣ה אֱלֹהֶ֔יךָ כֹּרֵ֥ת עִמְּךָ֖ הַיּֽוֹם׃
что ты должен войти в завет Господа Бога твоего—и в Его клятве—что Господь Бог твой делает с тобою в этот день;
Tze'enah Ure'enah
“With its sanctions” [29:11]. With an oath. The Holy One commanded an adjuration and an oath. He will not exchange Israel and they will be His people forever, even when they will be evil. God is their God forever, as the verse says, “seeing that the Lord undertook to make you His people” [I Samuel, 12:22]. This means that the Holy One swore that Israel should be His people. The word “seeing that” means to swear, just as the word alah also means to swear.3Bahya, Deuteronomy, 29:11.
Rashi
לעברך means THAT THOU SHOULDEST PASS [INTO THE COVENANT]. It would not, however, be correct to explain it as meaning “to make thee pass” (when the suffix would be objective), but it must be explained like (Deuteronomy 4:14) לעשתכם אתם, “that ye may do them”.
Ibn Ezra
to cross over a verbal noun. The word is used in its idiomatic sense (cf. “they passed between its sections” [Jeremiah 34: 18]). Note that when not followed by the preposition into, the word has the exact opposite meaning.