The Mishna had stated: If one made a neder against tasting wine for the year, and the year was proclaimed to be a leap year, he is forbidden for the year and its extension.

The Ra”n explains: The Mishna is teaching us that even if one made the neder from the beginning of the year, since he said “this year,” we do not say that he meant “one year,” but rather, he is prohibited for an extra month, which is thirteen months. However, if he said “one year” without any specification, the extra month is not included, even though the year was a leap year. For behold, if he did not abide by his prohibition this year, he makes it up the next year, which is a regular year. And although, it is forbidden for him to do that, because there is a prohibition against delaying, since if he would delay, he could make it up in another year, his neder is not connected to this year, which is a leap year. Therefore, even if he fulfills it this year, the extra month is not included.

The Rashba holds that even if he says, “one year from today,” the extra month is not included.

It is evident from the Ra”n that he holds of the following novelty: One can violate the transgression against delaying, even by a prohibatory neder.

The Rambam and Ramban, both maintain that this prohibition is only applicable by a neder for hekdesh, when one is obligating himself to do something.

The Machaneh Efraim adds that this transgression can apply by all nedarim to fulfill a mitzvah.

Reb Shimon Shkop states that the Ra”n’s words are perplexing. The prohibition against delaying is applicable when the person has an obligation to do soemthing. A neder is a prohibition on an object. If the object is forbidden, it is forbidden, but if it is not, how can there be a prohibition against delaying?

Reb Dovod Pervarsky explains: A neder also begins with an obligation resting on the person. He is obligated to fulfill his neder. If the forbidden object is in existence, the neder takes effect upon that object. However, if it is not in existence at that time, the person has a responsibility to render it forbidden when it comes into this world. If he fails to do so immediately, he is violating the transgression against delaying.