1)
What the implications of "Ki Avodas ha'Kodesh aleihem"?
1.
Rashi and Seforno: It implies that K'has carried the Aron, the Shulchan and the other Keilim, which were intrinsically holy 1 - which is why they carried them on their shoulders and not on wagons.
1
Seforno: As opposed to the B'nei Gershon and the B'nei Merari, who only carried the components of the Mishkan.
2)
Why does the Torah write "ba'Kasef" (on the shoulders) and not 'be'Kasef' (on their shoulders)?
1.
Panim Yafos (in Bamidbar 7:9): Because one Levi stood outside the poles (on the left), and one stood between the poles. 1
1
Refer also to Sh'mos 30:4:151:1,2 & 4 and note.
