At the tent of meeting, Aaron and his sons were anointed as priests: ”And [Moses] poured some of the anointing oil on Aaron’s head and anointed him to consecrate him” (8:12). Not only did Moses establish Aaron and his sons as priests, but all the details – Aaron's coat, the sash, the ephod, the breastpiece with the Urim and the Thummin, the turban, the golden plate, and the holy crown – were appointed by Moses. And then, the offerings precisely as the Lord commanded. Once, again, all this is a good reminder that, in approaching God, there is a right way. Of course, we do not have to do all that Aaron and the people of Israel did in order to approach God. We have a great High Priest, who has entered the heavenly Holy of Holies, and through whom we have free access to the Father! These themes seem to keep popping up: right worship of God, right preparation to worship God, and priestly intercession. But, then, it is necessary, from generation to generation, to remind everyone of these things.
As if to emphasize that, indeed, there is a right and a wrong way to approach God, Moses tells the story of Nadab and Abihu, who brought unauthorized incense and fire before the Lord. On the one hand, someone might wrongly, in protest, reject all the detail and complicated manners of approach. On the other hand, we might be thankful that God instructed Israel in the right manner of approach, and that instruction for their own benefit, and that God has now provided for us free approach through his Son.
My soul, be on thy guard;
ten thousand foes arise;
the hosts of sin are pressing hard
to draw thee from the skies.
Ne'er think the vict’ry won,
nor once at ease sit down;
the arduous work will not be done
till thou hast got the crown. --George Heath (1781)