And Moses took the blood. Moses continues still to act as priest, and the new sacrifice is once offered by him. He performs the priestly act of presenting the blood; but on this occasion, which is special, the blood is not dealt with in the manner prescribed for the high priest's offerings (Leviticus 4:6).
The reason of this is that Aaron was not yet high priest, and also that the offering was made not only for Aaron, but also for his sons; and further, the blood as well as the anointing oil was required to purify the altar, and sanctify it (see Hebrews 9:21).
Although the blood was not "brought into the tabernacle," yet the bullock was burnt with fire without the camp, not eaten according to the rule of Le Leviticus 7:26, Leviticus 7:30. This was necessary, as there were as yet no priests to eat it.