Musar do Kapłańska 4:21

And the brunt of the responsibility lies in the city dignitaries, who have the power to protest and to amend, as Chazal have said on the verse, Vayikra 4:21: "It is the sin-offering for the assembly," followed by (Ibid. 21): "If a leader sin," to teach us that the sin of the assembly is the sin of the leader, in that he is held responsible for not seeing to it to correct matters.