Leviticus 16:11

And Aaron shall bring the bullock. — Having formally dedicated the bullock for his own sin offering (see Leviticus 16:6), and after the two goats which constituted the people’s sin offering had been presented and their lots decided (Leviticus 16:7), Aaron comes back to his own sin offering a second time. He again laid both his hands on the victim and repeated the confession for himself, for his house, and for the whole priesthood, as given in Leviticus 16:6.

And shall make an atonement for himself. — His own sins had first to be expiated before he could offer the atoning sacrifices for the people. (Comp. Hebrews 5:3; Hebrews 9:7.)

And shall kill the bullock. — Being a sacrifice offered up for himself the high priest, like any layman, had to slaughter the victim, and could not delegate this work to anyone else. (See Leviticus 1:5.) He received the blood in the sprinkling bowl, which he handed over to a priest to stir the blood lest it should coagulate while he performed the fumigation.