Aaron’s ordination has been completed. Going into the tent symbolizes his new role as the high priest. It may also demonstrate that the priesthood, rather than Moses alone, will now mediate between the Lord and his people. This is reinforced by the realization that this is the first time that Moses enters the holy place, though he had free communication with God outside the sanctuary. This marks a change in the way that the Lord deals with his people.
23 And Moses and Aaron went into the tent of meeting, and when they came out they blessed the people, and the glory of the LORD appeared to all the people.