וְלָקַחְתִּ֨י אֶתְכֶ֥ם לִי֙ לְעָ֔ם וְהָיִ֥יתִי לָכֶ֖ם לֵֽאלֹהִ֑ים וִֽידַעְתֶּ֗ם כִּ֣י אֲנִ֤י יְהוָה֙ אֱלֹ֣הֵיכֶ֔ם הַמּוֹצִ֣יא אֶתְכֶ֔ם מִתַּ֖חַת סִבְל֥וֹת מִצְרָֽיִם׃
너희로 내 백성을 삼고 나는 너희 하나님이 되리니 나는 애굽 사람의 무거운 짐 밑에서 너희를 빼어낸 너희 하나님 여호와인줄 너희가 알지라
Ramban
AND I WILL TAKE YOU TO ME FOR A PEOPLE. That is, when you will come to Mount Sinai and you will accept the Torah. There, [at Mount Sinai], it was said, Then ye shall be Mine own treasure.41Further, 19:5.
Sforno
ולקחתי אתכם לי לעם, this will occur at the revelation at Mount Sinai.