Leviticus 4:2

Speak with the sons of Israel, saying: When a man hath sinned inadvertently against any of the commandments of the Lord (in doing) what ought not to be done, and he hath done it against any one of them:

if anyone sins by mistakenly doing something that is prohibited, and punishable either by karet or by flogging anyone includes both the native born and the convert, as it is written [Numbers 15:15]. Scripture now goes into the details, beginning with the High Priest (i.e., the kohen who is anointed).

IF A SOUL SHALL SIN IN ERROR. Since the process of thinking is centered in the soul, and it is the soul which commits the error, Scripture mentions here nefesh (soul). The reason for the offerings for the erring soul is that all sins [even if committed unwittingly] produce a particular “stain” upon the soul and constitute a blemish thereon, and the soul is only worthy to be received by the countenance of its Creator when it is pure of all sin. Were it not so, then all the fools of the world would be deserving to come before Him. It is for this reason that the erring soul brings an offering, through which it becomes worthy of approaching unto G-d who gave it. It is on account of this that Scripture mentions here nefesh (soul). Our Rabbis have interpreted: 1:1. “‘Nefesh’ (A soul) — this [word is used to] include proselytes and slaves” [thus teaching us that they too are under the obligation of bringing this offering, since the term nefesh is inclusive of them as well].
Now in the case of the sin-offering of the anointed priest [first discussed here in Verses 3-12], He does not say “and [the priest] shall make atonement for him, and he shall be forgiven,” as He mentions in the case of other sinners — namely, the whole congregation, the prince, and the common man. Perhaps the reason for this is that due to his great importance he cannot obtain atonement nor be forgiven completely until he prays and beseeches his G-d, for he is the messenger of the Eternal of hosts, and he must be of clean and pure hands [so that he can never be reproached with anything; hence in addition to the offering he must bring, he must also pray especially for forgiveness].
Scripture does not mention here, when speaking about the bulls which were to be entirely burnt, that the burning of those portions offered on the altar is “of a pleasing odor,” or that it is “a fire-offering unto the Eternal.” The reason for this is that since part of them is burnt outside [the camp of Israel], it is therefore not for “the fire unto the Eternal.” In the case of the goat of the prince [which he brings as his sin-offering], He mentioned “atonement” [and the priest shall make atonement for him] but did not state that it is “a fire-offering, of a pleasing odor unto the Eternal,” because the offering is a sa’ir (a goat). brought in case of idol worship (Numbers 15:24) (Ma’or V’shamesh). See also Ramban at the end of 3:1. In the case of the sin-offering of the common person, He mentions that it is for a pleasing odor unto the Eternal, but does not mention “a fire-offering,” for it is self-understood that it is such, since the whole purpose of the fire-offering is to the Eternal. The student learned [in the mystic lore of the Cabala] will understand.

אשר לא תעשינה, all the negative commandments violation of which carries the karet penalty when the violation was deliberate. There are only two positive commandments for which there is a karet penalty, where for the mere deliberate omission of performing the commandment the penalty is equal to corresponding negative commandments. They are Pessach, failing to bring or participate in eating of that offering at the right time, and failure to circumcise oneself if this rite has not been performed on one as a baby.

מאחת מהנה, our sages in Torat Kohanim under the heading of חובה, consider this to mean “part of a whole,” as for instance the letters שם of the name שמעון, i.e. if one intended to write the name שמעון but was interrupted after having written the first two letters, seeing that they make sense one is liable for having performed the whole אב מלאכה of “writing.”

נפש כי תחטא בשגגה, “if someone commits a sin inadvertently;” it is noteworthy that the verse does not commence with the word: אדם, “a human being,” as it does in Leviticus chapter one verse two, where it describes someone feeling the urge to offer a sacrifice to the Lord. When the prophet Ezekiel in Ezekiel 18,4, writes about the same subject, he too commences by referring to the subject as נפש, i.e. the animalistic part of our soul. The point that is being made in both these verses is that a sin can only be the product of the animalistic life force in our body, not the spiritual part that G–d blew into Adam’s nostrils when the result was his becoming a human being, אדם. (Compare Genesis 2,7 where he is then described as נפש חיה, “a living creature,” not just as נפש.) The creature described as נפש, is by definition mortal, as is clear from the verse quoted from Ezekiel 18,4, where the prophet concludes with the word: תמות, “it is bound to die.” Consider the following parable: two subjects had each committed a trespass against their king. One is an ordinary citizen, whereas the second one was one of the people engaged by the palace where he made his living. They were both arraigned for judgment. The King decreed that the ordinary citizen was to be released forthwith, whereas he imposed a painful penalty for the member of the palace staff who had committed a similar offence. The other members of the palace staff were very disturbed when they observed that their colleague had been singled out for harsher punishment. They questioned the king about this. The King told them that the first citizen, being a stranger, was not familiar with the good qualities of the king. He could therefore be forgiven for having committed this trespass. The palace employees, however, who were well aware of all the king had done for them, could not be forgiven for having trespassed against his rules instead of being especially careful not to commit such an offence. The same applies to creatures who possess only a body, i.e. who though human, did not have a Divine soul, which made them part of the heavenly regions, i.e. they are part of the staff of G–d’s Palace. They are charged with ensuring that their “uniform,” the soul, is in a state of purity at all times. As a result of this difference, the bodies who did not receive a נשמה, a soul from heaven, when they die are buried and this is all. Human beings endowed with a heavenly soul, however, come up for judgment to determine if the G–d given soul is being returned in the condition it had been given to them.