וְזֹ֖את הַתּוֹרָ֑ה אֲשֶׁר־שָׂ֣ם מֹשֶׁ֔ה לִפְנֵ֖י בְּנֵ֥י יִשְׂרָאֵֽל׃
И это закон, который Моисей поставил перед детьми Израиля;
Rashi on Deuteronomy
וזאת התורה AND THIS IS THE LAW — this which he was about to set forth after this chapter.
Sforno on Deuteronomy
וזאת התורה, the theoretical, philosophical part of the Torah. The word זאת refers to what has just been concluded.