Why does the Torah refer here to Gershon and Merari as "Nos'ei ha'Mishkan" and in Pasuk 21, to K'has, as "Nos'ei ha'Mikdash"?
Rashi (in Pasuk 21): Because whereas Gershon and Merari carried the curtains and the planks, K'has carried the Aron and the other holy Keilim.
What was the procedure regarding the carrying?
Rashi and Ramban #1: As soon as Degel Yehudah began to travel, Aharon and his sons took down the Paroches and covered the Aron 1 (and the other holy Keilim, 2 and arranged the poles) 3 and the B'nei Gershon and Merari dismantled the Mishkan, loaded the wagons and followed Degel Yehudah. 4 Whereas K'has waited for Degel Reuven to travel, after which they picked up the holy Keilim and followed them. 5
Ramban #2 (citing a Beraisa): See answer #1. Gershon and Merari traveled behind Machaneh Reuven and K'has, behind Efrayim. 6
Rashi: As the Pasuk stated in 4:5. Oznayim la'Torah: They did this first, so that the Aron and the other Keilim should not be left stsnding in the open after the Mishkan had been dimantled.
Rashi (on Pasuk 21): The Shulchan, the Menorah and the two Mizb'chos.
As described at the end of Naso.
As stated in this Pasuk.
As stated in Pasuk 21. See also Rashi in Divrei Hayamim 1, 28:10.
See Ramban, who reconciles the Beraisa with his first explanation, which fits better into the Pesukim.
