Numbers 3 has much to say about the persons and their duties. We need to dwell on this because it actually concerns us and our duties.
First, we will consider the duties of the priests and then the duties of the Levites. The priests are the anointed ones who serve God directly.
"Those to encamp before the tabernacle on the east, before the tent of meeting toward the sunrise, were Moses and Aaron and his sons" (v. 38a). Here we see that the priests were to camp before the tabernacle, on the east, toward the sunrise. The priests were actually gate guards, guarding the entrance to the tabernacle. Anyone who wanted to serve God had to first pass through the priests.
The priesthood today is no longer a household matter as it was with Aaron; the priesthood is universal. Nevertheless, the principle remains the same. Not everyone can pass through the gate guard to reach the ark within the veil. Those who want to do this must first pass through the priesthood. Once a believer has passed through the priesthood which guards the tabernacle, he has the right to enter into the tabernacle, pass through the second veil, and reach the ark, where God meets with His people.
The priesthood today is universal. This means that every believer is a priest and should serve as a priest. However, not every believer actually functions as a priest.
The priests were to keep the charge of the sanctuary (vv. 38b, 32). The sanctuary was the tabernacle with its two sections, the Holy Place and the Holy of Holies. The word charge refers to responsibility. For the priests to keep the charge of the sanctuary meant that they were responsible for the entire sanctuary and everything related to it. If anything were damaged or stolen, the priests were responsible.
The priests were to keep the charge of the tabernacle "for the charge of the sons of Israel" (v. 38b). Concerning the tabernacle, a number of charges were given by God to the children of Israel. They were supposed to do certain things and were not supposed to do other things. If the people kept these charges, it was fortunate for the priests. If the people could not keep God's charge, the priests were held responsible. The priests were to correct the people or keep them away from the sanctuary or fulfill the charge for them. This is what it means to say that the priests kept the charge of the sanctuary for God's charge to the children of Israel.
If we have experience in the spiritual service of God, we will realize that, in principle, the New Testament priests bear the same responsibility today. We not only bear the charge of the sanctuary ourselves, but often we must bear the responsibility for others' service. If they do something wrong, we should correct them and also instruct them to do the right thing. The crucial point here is that the priests are charged to take care of God's holy dwelling place.
"The stranger who comes near shall be put to death" (v. 38c). The stranger here was a layman, someone who was not a priest. Any layman who came near was to be put to death.