The fifth perek (=chapter) of Masechet Shevu’ot, Perek Shevu’at ha-Pikadon, begins on today’s daf (=page). According to the Torah (Sefer Vayikra 5:21-26), if someone has received something to watch and denies having it when the owner asks to get it back, swearing falsely, he will be obligated not only to return the object, but he will also have to pay an additional 20% as a penalty, and bring an asham sacrifice in addition. This law does not apply only to situations of pikadon – when the person was watching the object for his friend, rather it applies to virtually all cases where a person is holding his friend’s property and swears falsely that he is not. In fact, the sacrifice that is brought is referred to as an asham gezeilot – an asham sacrifice brought as atonement for robbery (the laws of this sacrifice and the associated monetary penalty are discussed at length in the seventh perek of Masechet Bava Kamma).
According to the Mishnah, the laws of shevu’at ha-pikadon apply to both men and women, whether they are related or not, whether the defendant is someone who is reliable and believed by bet din or not. Rashi, as well as other commentaries, suggest that this list is unnecessary. Given that the halakhah discussed here involves someone who denies a monetary obligation it should be obvious that it applies equally to all. They argue that the Mishnah includes this list for stylistic reasons, specifically in order to parallel – or contrast with – the Mishnah at the beginning of the last perek(30a), where we learn that shevu’at ha-eidut does not apply to all people equally.
The Tiferet Yisrael, however, suggests that there may be a reason to mention each of these cases specifically. Since in Talmudic times women did not ordinarily control their own finances, I might have thought that a claim against a woman was not a true monetary claim. Regarding relatives, I may have thought that since they were likely in a position to inherit that claimant, perhaps the law should not apply. Finally, I might have thought that those whose oath would not be accepted in court may not be held liable for any oath that they take.