Why does the Mishkan need to be guarded?
R. Bachye (citing Sifri Zuta) and Oznayim la'Torah (citing the commentaries at the beginning of Tamid): Due to the prestige of the Mishkan - One canot compare a palace that is not guarded to one that is . 1
See Oznayim la'Torah, who discusses the opinion of the commentaries who hold that the Mishkan had to be guarded day and night.
What do "Mishmart'cha u'Mishmeres Kol ha'Ohel" incorporate?
Seforno: They incorporate the Kodesh Kodshim and the Kodesh, respectively - which the Levi'im guarded from outside the boards of the Mishkan.
What is the definition of "K'lei ha'Kodesh" and "ha'Mizbe'ach" that are mentioned here?
Seforno: "Klei ha'Kodesh" refers to the three Keilim that are inside the Kodesh - the Menorah, the Shulchan and the Mizbach ha'Zahav - and ha'Mizbe'ach", to the Mizbe'ach ha'Olah - even though it is outside the walls of the Mishkan.
What are the implctions of "Gam Heim Gam Atem"?
R. Bachye (citing the Sifri): It teaches us that a Kohen who perform the Avodah of a Levi or vice-versa, and even if a Levi who is designated to guard, sings, or vice-versa, 1 transgresses a La?av and is Chayav Miysah. 2 3
Arachin 11a #2: It teaches us that the main Avodah of the Levi'im, like that of the Kohanim, concerns the Mizbe'ach - Shirah, which they performed whilst the Korban Tamid was being brought. 4
