What are the ramifications of the word "Koh"?
Rashi: Moshe was to say the following words without change. 1
What are the ramifications of this Pasuk?
Rashi: It is impossible to deny what one has seen! 1
Ramban: Having seen with their own eyes what they saw and that Hashem is Master over Heaven and earth, Yisrael are prohibited from adopting or making any other gods. 2
Seforno: It serves as a practical lesson that, although Hashem dwells in the Heaven, He lowers Himself to supervise His creations and to communicate with them. 3
How will we reconcile this Pasuk with the Pasuk earlier (Shemos 19:20) that Hashem descended upon Har Sinai and spoke to Yisrael from there?
Rashi #1: Hashem's Kavod in the form of His Voice) was in the Heaven - to chastise them, and His fire and great might were on earth. 1
Ramban: Hashem was in Heaven and His Kavod (in the form of the fire) was on Har Sinai. 2
Rashi #2: He bent the Heaven and the Heaven of the Heavens and spread them on the Mountain. 3
As the Pasuk indicates in Nechemyah, 9:13 (Ramban). The Ramban agrees with Rashi's quotations, but disagrees with his interpretation. The Ramban also quotes the Ibn Ezra, who cites Shemos 33:21 (See Rav Chavel's notes).