(3) if the anointed priest shall sin so as to bring guilt on the people, then let him offer for his sin, which he hath sinned, a young bullock without blemish unto the LORD for a sin-offering.

(3) אם הכהן המשיח יחטא לאשמת העם IF THE PRIEST THAT IS ANOINTED DO SIN לאשמת העם — Its literal sense is this: When the High-priest sins this is the guilt of the people (i. e. it results in the people remaining under a load of guilt), because they are dependent on him to effect atonement for them and to pray on their behalf, and now he himself has become degenerate and can thus not expiate for them, wherefor they remain under guilt.

Another thing: "If the appointed priest should sin..." This is referring to an instance in which the appointed priest who absolves others of sin, needs to be absolved himself.

Torah begins with the High Priest, the one who is "least likely to commit a sin", and writes: אם הכהן המשיח יחטא לאשמת העם, implying that a sin by the High Priest is most likely the outcome of guilt by the people, their conduct having contributed to his committing such an error. The Talmud quotes that if someone makes an error in their private prayer this is a bad omen for them. If, however, the cantor, i.e. the person hired to pray on behalf of the people, makes an error, all those on whose behalf the cantor offered prayers will suffer the consequences of their error.

"For the guilt of the (entire) Nation" -- This teaches that either the Priest is culpable for the guilt of the entire nation... or it teaches that the guilt of the entire nation is actually made up of the individual guilty acts of each person. And it is mentioned in relation to the the priest as he is a carrier (representative) of Torah...

"Regarding his sin" -- Regarding his personal sin

(16) He used to say: It is not your responsibility to finish the work, but neither are you free to desist from it...

(2) Speak to the Israelite people thus: When a person unwittingly incurs guilt in regard to any of the LORD’s commandments about things not to be done, and does one of them—