They can find grounds to annul a neder by [reason of] festivals or Sabbaths. At first they used to say: Those days are permitted, but all the other days are forbidden —- until R' Akiva came and taught that a neder which has been nullified in part is nullified in its entirety.

How? [In a case where someone] said: “Konam, what benefit I derive from any of you,” if one of them is permitted —- they are all permitted. “What I benefit from this one and from this one,” if the first one is permitted —- they are all permitted; if the last one is permitted —- the last one is permitted, but all the others are forbidden; if one in between is permitted —- from him and down are permitted, from him and up are forbidden. “What I benefit from this one is korban, and from this one, korban” —- grounds to annul each neder are needed.