What are the connotations of the word "ve'es Aharon ve'es Banav Tifkod"?
Rashi: It means 'You shall appoint!' 1
Rashbam: It means appoint Aharon and his sons officers over the Levi?im. 2
See Oznayim la'Torah.
Rashbam: As in Mikeitz Bereishis, 40:4 ?Vayifkod Sar ha?Tabachim es Yosef?.
What is "ve'es Aharon ve'es Banav Tifkod" referring to?
Rashi and Rashbam: It refers to the appointment of the Kohanim - to the Avodos of the Kohanim, 1 as the Pasuk goes on to explains.
Rashbam: It refers to the appointment of Aharon and his sons over the Levi'im.
Rashi: Kabalas Damim, Zerikah, Haktarah and the other Avodos that are confined to the Kohanim.
What is "ve'Shamru es Kehunasam" referring to?
Rashi: Refer to 3:10:1:1*.
Seforno: It refers to the Kohanim guarding the areas from the Mizbe'ach and inwards, as well as inside the Paroches, to prevent the Levi'im from entering.
Oznayim la'Torah: Although the Levi'im have been instructed to assist the Kohanim, the Torah is instructing the Kohanim to refrain from asking them to help with any Avodah that requires Kehunah - and in anticipation of the Levi'im, who will want to help the Kohanim in those areas too, the Pasuk concludes "ve'ha'Zar ha'Kareiv Yumas"
What is "ve'ha'Zar ha'Kareiv Yumas" referring to?
Seforno: It is referring to a Zar who comes to perform the Avodah of a Levi or of a Kohen?