Why Aaron Laid His Hands on the Sin-Offering Bullock

13) "and Aaron and his sons placed their hands on the head of the bullock of the sin-offering.": We find that Aaron and his sons perform semichah (the placing of the hands) on all of their offerings. But because they do so because they are their offerings, the offerings of partners are compared to their offerings, viz.: Just as their offerings require semichah for each of the participants, so the offerings of partners require semichah for each partner.