3:38 But those that encamp before the tabernacle toward the east, [even] before the tabernacle of the congregation eastward, [shall be] Moses, and Aaron and his sons, keeping the charge of the sanctuary {n} for the charge of the children of Israel; and the stranger that cometh nigh shall be put to death.
(n) That no one should enter into the tabernacle contrary to God's appointment.
3:38 For the charge - Either in their stead, that charge which they were obliged to keep, if God had not committed it to those: or for their benefit; for their preservation, as the word may be rendered.
3:14-39 The Levites were in three classes, according to the sons of Levi; Gershon, Kohath, and Merari; and these were subdivided into families. The posterity of Moses were not at all honoured or privileged, but stood upon the level with other Levites; thus it was plain, that Moses did not seek the advancement of his own family, or to secure any honours to it. The tribe of Levi was by much the least of all the tribes. God's chosen are but a little flock in comparison with the world.