Charles Ellicott Commentary Leviticus 4:2

"Speak unto the children of Israel, saying, If any one shall sin unwittingly, in any of the things which Jehovah hath commanded not to be done, and shall do any one of them:" — Leviticus 4:2 (ASV)

If a soul shall sin. It will be seen that while the three previous kinds of offerings, namely, the burnt offering (Leviticus 1:1–17), the grain offering (Leviticus 2:1–16), and the peace offering (Leviticus 3:1–17), are spoken of as familiarly known and practiced among the Israelites before the giving of the Law, the sin offering and the trespass offering are here introduced as a new injunction. Here, we no longer find the voluntary formula, If any man of you bring, etc. (Leviticus 1:2; Leviticus 2:1; Leviticus 3:1), as you are accustomed to bringing; but rather, if a soul shall sin ... let him bring for his sin offering a young bullock, etc.

Through ignorance. He did it inadvertently, and at the time of its commission did not know that it was a transgression, but recognized it as a sin after he did it. (Leviticus 4:22; Leviticus 4:27; Leviticus 5:18; Leviticus 22:14.) According to the practice that was practiced during the second Temple, the sin here spoken of, for which the sin offering was brought, was:

1. A sin committed through ignorance, or involuntarily, as opposed to a sin committed with a set purpose .
2. A sin against a negative command.
3. A sin that consisted in acts, not in words or thoughts, as is deduced from the expression and shall do against any of them;.
4. Acts of such a nature that, if committed intentionally, they would subject the sinner to the awful punishment of excision .