One who says to his wife: “All the nedarim which you shall make, from now until I return from such and such a place are confirmed,” he said nothing. [But if he says:] “they shall be revoked” —- R' Eliezer says: [They are] revoked. The Sages, however, say: [They are] not revoked. Said R' Eliezer: If he can revoke nedarim which are already binding, should he not be able to revoke nedarim which are not yet binding? They said to him: It says (Numbers 30:14): Her husband can confirm it, and her husband can revoke it —- that which can be confirmed can be revoked; that which cannot be confirmed cannot be revoked.