Or HaChaim on Leviticus 4:13/אור החיים על ויקרא ד׳:י״ג

1 ואם כל עדת ישראל ישגו, And if the entire community of Israel shall err, etc. The word עדת, "community of" is taken by Torat Kohanim as referring to the Sanhedrin, the Jewish Supreme Court. The word עדה in this verse and the word עדה in Numbers 35,24-25 both are a reference to the Sanhedrin of 71 sages. The word ישראל is presumed to mean the Court which is unique to Israel, i.e. the Court comprising 71 judges. The word ישגו teaches that the legislation introduced here applies only if the Court erred in its judgment and the people acted upon that error in judgment. If the members of the Court themselves acted upon their faulty judgment this is still no reason to apply the legislation stated in this paragraph seeing that the Torah writes הקהל ועשו, "and the community did accordingly." Thus far the Torat Kohanim.

2A moral-ethical approach to this verse considers the word ישגו as referring to Israeli society committing moral errors and departing from Jewish norms. As a result of such conduct it would follow that the Jewish Supreme Court will also hand down faulty judgments as the judges and their Torah knowledge reflect the level of the people whom they represent. They are to blame for the people straying as they had not used their authority in controlling public morals. It had been their duty to discipline the individuals who were responsible for a trend away from traditional Jewish values. We have the example of Abbaye in Gittin 60, who erred in a ruling as he had not first obtained permission from his teacher to issue a ruling. We have been told this specifically in Sanhedrin 5.