Why does the Torah insert "Kol ha'Eidah"?
Rashi: Because all of the previous generation on whom Hashem had decreed had died and the Pasuk is now referring to those about whom the Torah writes 1 "Chayim Kulchem ha'Yom"?
What are the implications of "Hor ha'Har"?
Rashi: It was a small mountain atop a large one, like a small apple atop a large one.
Why didn't the Cloud that went in front of Yisrael flatten Hor ha'Har?
Rashi: The Cloud flattened all the mountains in its path except for three - Har Sinai (for the Torah); Har Nevo (for the burial of Moshe, and Hor ha'Har (for the burial of Aharon).