Moses (for the last time) and Aaron (for the first time) went into the tabernacle in the character of priest. During this visit Moses committed to Aaron the care of the things within the tabernacle, as he had already given him the charge of all connected with the sacrifices of the court.
Not till after this is Aaron fully initiated into his office. "No man taketh this honour unto himself, but he that is called of God, as was Aaron" (Hebrews 5:4). On coming out from the tabernacle, Moses and Aaron, standing near the door, unite in blessing the congregation, in order to show the harmony between them and the capacity of blessing in the Name of the Lord enjoyed by Aaron as by Moses.
The latter has now divested himself of that part of his office which made him the one mediator between God and his people, Aaron is henceforth a type of Christ as well as Moses. While giving the joint blessing, the glory of the Lord appeared unto all the people, proceeding from the ark, and enveloping the lawgiver and the priest as they stood together.