This is what you are to do for Aaron and his sons based on all that I have commanded you, taking seven days to ordain them.
Here is, I. The law concerning the consecration of Aaron and his sons to the priest's office, which was to be done with a great deal of ceremony and solemnity, that they themselves might be duly affected with the greatness of the work to which they were called, and that the people also might learn to magnify the office and none might dare to invade it. 1.
Commenting on Exodus 29:1-37
And thus shall thou do unto Aaron, and to his sons,.... For their consecration, washing, clothing, anointing them, sprinkling blood upon them and their garments, and offering sacrifice for them: according to all things which I have commanded thee; no one thing was to be omitted, and we find they were carefully and punctually observed, Lev 8:1.
seven days shalt thou consecrate them--The renewal of these ceremonies on the return of every day in the seven, with the intervention of a Sabbath, was a wise preparatory arrangement, in order to afford a sufficient interval for calm and devout reflection (Heb 9:1; Heb 10:1).