The third perek of Massekhet Shevuot begins on today’s daf and with it the Gemara turns its attention to the main subject of the tractate – the issue of oaths – a topic discussed in a number of places in the Torah.
In the Ten Commandments (see 20:6) the Torah forbids taking God’s Name in vain, which is understood to be referring to the context of an oath. In Sefer Vayikra the Torah forbids false oaths (see 19:12). These types of oaths are referred to by the Sages as shevuot shav.
In Sefer Vayikra (5:4-10) the Torah also requires that someone who takes an oath le-hara o le-hetiv – committing to perform a positive act or to refrain from doing something – fulfill his statement. This is referred to by the Sages as a shevuat bituy.
Shevuat bituy refers to a situation where a person makes a positive or a negative statement, either regarding past events or future ones. If it was made regarding the future, it is similar to a vow, and will be treated as a false oath if he does not fulfill the statement that he made. The difference between a shevua and a neder lies in the fact that a shevua is what a person accepts upon himself, while a neder relates to the object under discussion, and in the different sacrifices that are brought if they are not fulfilled. If the shevuat bituy was made regarding past events, if his statement was false, he is held liable immediately – if it was done knowingly, he will receive malkot (lashes) and if unknowingly, he will have to bring a sacrifice according to his financial standing.
Shevuat shav is a type of false oath, when a person takes an oath that he will do something that cannot be done, or if he tries to affirm a false statement that he made by means of an oath or if he swears for no reason at all. In these situations he will be liable to receive malkot if he did it knowingly; if unknowingly there is no punishment.