1)
"Vayedabeewr Hashem el Moshe be'Midbar Sinai ? ". Why does the Torah need to insert "be'Midbar Sinai" here?
1.
Ramban: Because the Torah wrote in Pasuk #1, that Hashem chose Aharon and his sons t be Kohanim on Har Sinai, it needed to point out that He designated the Levi'im (later) in Midbar Sinai, but not on Har Sinai.
