Sforno on Numbers 18:1/ספורנו על במדבר י״ח:א׳

1ואתה ובניך ובית אביך אתך תשאו את עון הקודש, you are responsible to prevent unauthorised people, i.e. ritually impure ones and non-priests from entering sanctified domains near the Tabernacle. This is a collective responsibility of all the priests. If unauthorized people nonetheless enter such domains due to inadequate surveillance you will be responsible for such a sin having occurred.