The purpose of Matan Torah was to draw down the holiness of Hashem into this physical world. Moshe Rabaynu appears to the Jewish people and he tells them three things. First, that Hashem chooses them as a special nation. Second, that they are ministers in charge of the reality around them; representing serving Hashem through the physical mundane world by harnessing and elevating everything for holiness- the actual purpose of Mathan Torah. The third thing is that they are a holy nation, represented by designating time every day to do Torah and mitzvahs.

לקו״ש י״ח