Why does the Torah switch from "Sa es Rosh" - by Yise'elim, to "Naso es Rosh" - by Levi'im?
Oznayim la'Torah: "Naso" is a Lashon of 'Nesi'us' (elevation) - in which case the difference speaks for itself.
What are the implications of "mi'Toch B'nei Levi"?
Oznayim la'Torah: It implies that, on the merit of Moshe and Aharon, K'has was elevated above Gershon and Merari, 1 inasmuch as they carried the holy vessels (that were Kodesh Kodshim) - the Aron, the Menorah, the Shulchan and the two Mizb'chos. 2
Oznayim la'Torah: By the same token the Torah, at the beginning of Nasi, writes "Naso" by Gershon, who carried the curtains, which were synonymous with "Mishkan", but not by Merari, who only carried the planks which supported them - presumably because he (Gershon) was the B'chor.
Oznayim la'Torah: And this also explains why, whereas earlier in the Parshah, the Torah lists them in their order of birth, here, where it is discussing the Avodah, it begins with K'has.
