Why was the Shok (the right calf) burnt with the Chalavim (and not given to Moshe together with the chest)?
Seforno (on Pasuk 2): Because the reason that the owner (if he is a Yisrael) gives the calf to the Kohen is because he (the Kohen) is about to enter the Ezras Kohanim, 1 where the owner is forbidden to go, whereas in this case, where the Korban was to inaugurate the Kohanim to enter the Mishkan, they placed it on the Mizbe'ach.
Refer to Sh'mos 29:22:4:1-2.
Sifsei Chachamim: In order to differentiate between Moshe, who was not a Kohen 2 , and Aharon and his sons, who, as Kohanim, were die to receive the Chazeh ve'Shok 3
Oznayim la'Torah: Because the Kohen receives the Chazeh as a gift,from Hashem as a remuneration for his efforts, whereas the Shok is a gift from the owner to the Kohen, who is his Shali'ach, and Moshe was not a Kohen. 4
And by the same token, the Nazir (upon the conclusion of his Nezirus) gives the right foreleg - which is equivalent to the hand - as well to the Kohen, handing over the work of his hands , which, until now was been dedicated to the service of Hashem (Seforno).
This also explains why Moshe served in a white robe (a Kittel) during the seven days of the Milu'im, and not in the Bigdei Kehunah.
As the Torah wrote earlier ? in 7:33-34.
