His charge, i.e. Aaron's charge, or those things which are committed principally to Aaron's care and oversight, and under him and his direction to the Levites. Of the whole congregation, i.e. of all the sacrifices and services which are due to the Lord from all the people, and because all the people could not and might not perform them, or at least divers of them, in their own persons, therefore they were to be performed by some particular persons in their name and stead; formerly by the first-born, Numbers 8:16, and now by the Levites. See Numbers 1:53, Numbers 16:9. Before the tabernacle, emphatically; not within the tabernacle, for the care of these things within the holy place was appropriated to the priests, as the care of the most holy place was peculiar to the high priest.
Related Commentaries of Numbers 3:7
Numbers 3:7
7 And they shall keep his charge, and the charge of the whole congregation before the tabernacle of the congregation, to do the service of the tabernacle.