Matthew Poole and continuators on Numbers 1:49

49 Onely thou shalt not number the tribe of Levi , neither take the sum of them among the children of Israel.

Because they were not generally to go out to war, which was the thing principally eyed in this muster, ver. 3, 20, 45. but were to attend upon the service of the Tabernacle, and therefore are reserved to another distinct muster, Numb. 3. 15. and 4. 2. &c. And least this should be thought to be designed and done through Moses his ambition to give his own Tribe the preeminence, he assures them it was done by Gods express command.