It is a common misunderstanding to think that during the times of the Temple, people who sinned could bring a sacrifice in order to receive atonement. In fact, a sin-offering could only be brought if the sin was committed accidentally. If someone purposely transgressed it is only his repentance (and, on occasion, punishment meted out by the court or by God) that can grant him atonement; an animal sacrifice cannot absolve an individual from punishment and teshuvah.
There are, however, rare occasions when a sacrifice is brought in response to a sin that was done on purpose. The Mishnah on today’s daf (=page) lists them. Among them are the cases of the asham – the guilt-offering – for shevu’at ha-eidut and shevu’at ha-pikadon.
Shevu’at ha-eidut are the laws governing cases where a person refuses to offer testimony, swearing that he does not have information that would be useful to his friend in court (see Sefer Vayikra 5:1).
Shevu’at ha-pikadon refers to a case where someone receives something to watch and denies having it when the owner asks to get it back, swearing falsely about the matter (see Sefer Vayikra 5:21-26).
The Gemara explains that we learn that in the case of shevu’at ha-eidut the sacrifice is brought even when the false oath is taken purposefully because the Torah does not use the word ve-ne’elam – that it was “hidden” from him – as it does in other cases of sacrifice. The law of shevu’at ha-pikadon is derived from parallel language that appears both there and in shevu’at ha-eidut.
The Gemara in Massekhet Shevu’ot (daf 37) quotes Rav Kahane as asking whether in a situation where all of the requirements were in place for actual punishment – where the witnesses warned the perpetrator that his action is forbidden and that he will be punished for it – will the sacrifice suffice, or, perhaps it will be replaced by malkot – lashes – that are the ordinary punishment for such an act, or, perhaps we should require both malkot and korban (sacrifice).
The Gemara does not come to a clear conclusion in response to Rav Kahane’s question, and the ruling that remains is that no malkot are given in a case of shevu’at ha-pikadon; under all circumstances an asham sacrifice will be brought if someone holding property that belongs to another swears falsely that he does not have it in his possession.