Thus; in this manner, or upon these terms. With a young bullock, i.e. with the blood of it, as it is explained Leviticus 16:14. So it is a synecdoche, the whole put for the part. For as for the body of it, that was to be killed and offered without upon the altar of burnt-offerings. For a sin-offering, for his own and family's sins, for a goat was offered for the sins of the people.
Related Commentaries of Leviticus 16:3
Leviticus 16:3
3 Thus shall Aaron come into the holy place: with a young bullock for a sin offering, and a ram for a burnt offering.