Daber el b'nei Yisrael laimor, nefesh ki sechetah b'shgagah ... speak to the children of Israel saying, if a person sins inadvertently (Vayikra 4:2)
Most of the commentaries focus on the purpose of korbanos, choosing sides, as it were, in the well known disagreement between Rambam [as brought in the second section of Moreh Nevuchim] and Ramban. The latter takes the Rambam to task in unusually hard criticism, referring to Rambam's contention that the korbanot were a reaction to the nation's desire to continue their idol worship as divrei ha'vai - meaningless words. According to Ramban, the purpose of the animal sacrifice is to provide man with the chance to reflect upon his sins and become even more closely bound to Hashem. Through this kirvas Elokim he is ultimately protected from further sin, by realizing that it is he who should be paying with his life. The substitution of the animal in his place and the public nature of the sacrificial process provide man with the impetus and wherewithall to be more careful in the future.
Much of this week's parashah focuses on the korban chat'os - the sin offering. The Torah delineates various types and each has its own set of rules as well as common rules that govern each one. There is the offering brought by a kohen who has inadvertently transgressed the Torah through an incorrect ruling regarding any part of the Divine service (see 4:1-12). Because of his high station, and his position as a halachic decisor, the kohen is obligated to bring a special korban which differs from that which he would have to bring were his sin only related to his personal conduct.
This chat'as differs from the sin offering brought on behalf of the entire nation which had sinned because of an erroneous decision by the Sanhedrin (ibid. 4:13-21) and they both differ from the sin offering brought by the king - the political leader of the people (see 4:22-26). Here, the reference is to a king who commits a sin unrelated to his office; i.e., he sinned in the same manner as any other individual. Unlike the kohen whose individual korban is only brought when his sin concerns his public office, the king has a separate chat'as for both private and public sins. Rav Hirsch points out, because of his position of supreme authority, his sacrifice differs and he brings a male goat rather than a female sheep. Finally, there is the cha'tas brought by an individual who transgresses inadvertently (ibid. :27-35).
Sforno notes that in the pesukim preceding the korbanos of the kohen, the Sanhedrin and the individual, the Torah uses a conditional introductory phrase; e.g., nefesh ki sechetah - if a person sins (ibid. :2) or v'im kol adas Yisrael yishgu - if all of Israel shall act mistakenly (ibid. 13) or v'im nefesh achas techetah - if an individual should sin (ibid. :27). On the other hand, in introducing the parashah of the nasi who sins, the Torah states (ibid. :22), asher nasi yechetah - when the ruler sins - which seems to suggest a sense of inevitability. He notes that such is the character of office; the power that the ruler is given will lead him to sin for it corrupts him and makes him believe that what is forbidden to other is permitted to him. And if power corrupts, then absolute power corrupts absolutely.
He is therefore given a personal korban for his atonement, for it is insufficient for him to simply be contrite on the personal level. Rather, he brings a completely separate korban to remind him not to allow power to go this head. How prescient that this week's parashah should deal with such a topical issue, a ruler [or governor of a great State] guilty of the very kind of moral turpitude that he so strongly condemned in others. One wonders what kind of kapparah is necessary.