John Gills Exposition of the Bible Commentary - Exodus 29:11
And thou shalt kill the bullock before the Lord ,.... That is, Moses is ordered to do it, who now officiated as a priest, "pro tempore", Aaron and his sons not being yet completely invested with that office, or thoroughly consecrated to it; of which consecration this sacrifice was a part, and therefore could not with propriety be concerned in killing their own sacrifice; for that purpose, Moses therefore did it, and he did it "before the Lord"; Jehovah the Son gave him those orders to do it... read more
Matthew Henry's Complete Commentary - Exodus 29:1-37
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. The ceremonies wherewith it was to be done were very fully and particularly appointed, because nothing of this kind had been done before,... read more