29 And the holy garments of Aaron shall be his sons’ after him, to be anointed therein, and to be consecrated in them.

30 And that son that is priest in his stead shall put them on seven days, when he cometh into the tabernacle of the congregation to minister in the holy place.

We have a brief parenthetical here, which reiterates that Aaron and his descendants would make up the priest class, the only ones that could be consecrated to stand before the Lord.

What it says about putting the garments on the priests for seven days is explained further in the following verses of this chapter. Apparently, the offering of a bullock, two rams, and the various breads would be repeated over a period of seven days.

Presumably, this sort of repetition would impress the symbolic lessons deeper and deeper in the mind of the priest. It also signifies how we strengthen our commitment to the Lord by degrees, reaching greater and greater levels of discipleship as we go. Finally, there is a special significance to the number seven, suggesting fulfillment and completion. For example, seven days was the full measure of the creation of the Earth, and Naaman was commanded to bathe himself in the river Jordan seven times to be healed. Through a full measure of repeated consecration, the priest would be ready by-and-by to perform his holy duties.