What is the significance of the term "Avodas Matanah"?
Rashi, Ramban #1 (citing Rashi): Hashem gave the Avodah to the Kohanim.
Ramban #2: The Torah is teaching us here that the Avodas ha'Kehunah is not an onus, like the service of human kings, but a (precious) gift, which Hashem personally gave to the Kohanim for Kavod and glory. 1
Seforno: It means that Hashem handed the Levi'im to the Kohanim as a gift, to perform any task in the Mishkan that they ask them to.
Ramban: As the Gemara says in Sotah, 15a, commenting on Pasuk 8 (in connection with eating the Korbanos) "le'Mashchah"
What was the gist of Hashem's answer to the people's concern?
Rashbam (in Pasuk 2 & 7): In answer to Yisrael's complaint, 1 Hashem first issued them with a prohibition against entering the Mishkan, 2 then He ordered the Levi'im exclusively to perform the Avodah, 3 thereby ensuring that the people will have no reason to come near.