Annulling Future Vows
“One who doesn’t want his vows for the entire year to be binding should stand on Rosh Hashana and say: ‘Any vow that I will make in the future will be null and void’.”
In this manner our gemara explains the mishna on amud aleph, and this statement is codified in Shulchan Aruch Yoreh De’ah 211. This “nullification in advance” of his vows is qualified by certain conditions, which are specified in the gemara, and cited as halacha.
The main concern is that when the person makes a vow in the future, he doesn’t do it in a manner that “nullifies” his earlier declaration of future vows being meaningless. For example, if he recalls that he made the earlier statement, and nevertheless makes a new vow, this would be interpreted as “nullifying his nullification” — thereby resulting in a binding vow that he did not want. The Aruch Hashulchan points out that since we have the custom to say a fixed, communal prayer of “Kol Nidrei” on the night of Yom Kippur, we are not actually negating vows — past or future — but offering a prayer that
The Mindset for an Oath
“When an oath is imposed on a litigant in court, he is told: ‘Know that we impose this oath not based on how you interpret it, but rather based on how we and Hashem interpret it’.”
This halacha is taught on our daf and is cited in Shulchan Aruch Choshen Mishpat 87:20. The gemara illustrates an example of the significance of this warning by relating a story that occurred in the courtroom of Rava.
A man made a claim against a person who had borrowed money from him, and but failed to repay any of the loan according to the claim of the lender. The borrower, however, denied owning the entire amount, saying that he had repaid part of the loan and only owes the rest (Rabbeinu Nissim). The halacha in this case is that the “denier-admitter” must take an oath, while holding a Sefer Torah, to deny that he owes the part that he claims was already paid. At this point, the borrower asked the lender to please hold onto his walking cane so that the borrower could hold the Torah to make the oath. Little did the lender know that the borrower had put the amount of money that the lender claimed inside the cane before giving it to him to hold while making the oath! After making the oath that he had given the money to the lender, the lender became angry and even broke the cane — resulting in the money falling out and the truth being revealed for all to see.
The warning decreed by our Sages is to cancel the validity of an oath made with a trick like this. After being warned that his oath is to be interpreted as the court and Hashem say, and not as the oath-maker would like, a person who makes an oath “on his terms” is making a false and invalid oath.