Korban Chatat, then, is brought by a person who sinned and committed a serious transgression, one of a limited list of serious sins against God, but his sin was not premeditated or done intentionally. Meaning, this person did not realize at the time of the deed that he was sinning. A classic example is a person who was confused about the days of the week and, thinking that it wasn?t Shabbat, did things that are prohibited on Shabbat, such as lighting a flame, cooking, writing, etc. Another example would be a person who knew it was Shabbat but didn?t know that the act he was doing is forbidden on Shabbat. Actually, this person never intended to sin. If we had told him it was Shabbat or that the act he wanted to do was prohibited, he would have stopped. A person like this is not punished for his deeds since he did them without awareness of their significance. When the Temple stood, he would have had to bring a Korban Chatat, a sin offering, and atone for his sins by bringing a sacrifice.
This halacha might cause one to wonder: Why does someone have to atone for a sin he did unintentionally? Does Korban Chatat imply that a person is considered guilty even when his actions were done without awareness?
These questions were asked by the Ramban (Nachmanides, Rabbi Moshe ben Nachman, of the greatest Jewish thinkers of the Middle Ages, Spain, 13th century) in his book ?Torat Ha?adam?. In an interesting and profound commentary, he explains the need for atonement even for an act committed unintentionally.
Lack of awareness, claims the Ramban, is itself a sin. If a person is not accountable for his actions, like a person who is insane or who was under duress, he is not guilty. We find this written explicitly in the Torah. When a person is forced to commit a forbidden act, he is not held accountable. But unawareness does not provide a complete exemption from responsibility. If we go back to the example from earlier, a person in his right mind should not forget if today is Shabbat; a person aware of his Jewishness should check if the act he is about to do is allowed or forbidden. A person who lives with the awareness that he is meant to obey God should be aware of his actions and should not do anything until he has carefully checked that it is allowed and appropriate.Judaism wants a person to act only with intent and awareness. It demands that a person take responsibility for his actions and not behave recklessly. However, as opposed to laws in many countries where ignorance of the law is not a valid excuse exempting one from punishment, the Torah does not demand that a person who acted unintentionally be punished. The Torah demands that a person be aware so that he does not accidentally do things that are forbidden.