Recalling the Revelation at Sinai

In Parshat Va'etchanan Moshe mentions Ma'amad Har Sinai in three different places, and in each case it is mentioned as a subject in its own right, rather than incidentally. This raises the question: why is the great revelation mentioned three separate times in our parsha, with a distance of only a few verses in between them? Why is the discussion of the revelation not concentrated in one place in Moshe's speech? What is the purpose of all this commemoration, and in what context is it mentioned? By dividing the book of Devarim into separate units and analyzing the structure of Parshat Va'etchanan, we can learn about the intended goal of the mentions of the revelation - to elevate Israel and strengthen their faith in the validity of the covenant between them and God.