Leviticus 8:1

“And the Lord spake unto Moses, etc.] The following section or paragraph, relating to the consecration of Aaron and his sons, was delivered, according to Jarchi, seven days before the setting up of the tabernacle; but to me it seems to have been delivered after the setting it up, since it was out of the tabernacle that the Lord said all those things recorded in the preceding chapters; and after he had given out the laws concerning sacrifices, then he renewed the order for the consecration of Aaron and his sons, that they might offer them: saying; as follows.”

“MOSES CONSECRATES AARON AND HIS SONS. (Lev. 8:1-36) Take Aaron and his sons--The consecration of Aaron and his sons had been ordered long before (Exo. 29:1-46), but it is now described with all the details of the ceremonial, as it was gone through after the tabernacle was completed and the regulations for the various sacrifices enacted.”

“8:1-36 In Exod 28–29, the Lord gave Moses specific instructions for clothing and for ordaining Aaron and his sons as priests. In Exod 39:1-31; 40:12-16; and Lev 8, the commands were carried out. Moses didn’t just pass along the instructions verbally; he enacted the rituals to provide an example for the priests down to the last detail, just as the Lord had commanded him (8:9, 13, 17, 21, 29). Because the penalty for disobedience was death, God made sure the priests knew exactly what to do.”

“Consecration of the Priests and the Sanctuary (cf. Ex 29:1-37). - The consecration of Aaron and his sons as priests was carried out by Moses according to the instructions in Ex 29:1-36; Exo 40:12-15; and the anointing of the tabernacle, with the altar and its furniture, as prescribed in Exo 29:37; Exo 30:26-29, and Exo 40:9-11, was connected with it ( Lev 8:10, Lev 8:11). Lev 8:1-4 Lev 8:1-5 contain an account of the preparations for this holy act, the performance of which was enjoined upon Moses by Jehovah after the publication of the laws of sacrifice ( Lev 8:1). Moses brought the persons to be consecrated, the official costume that had been made for them (Ex 28), the anointing oil ( Exo…”