Nedarim 5 - How to properly vow
We learned earlier that one can formulate a simple vow, "I am separated from you," and the vow will take effect. However, who is forbidden to do what? This is now subject to interpretation.
Shmuel says, "He has to specify what exactly is forbidden." If he does not, there is no vow at all. This is because Shmuel follows the opinion of Rabbi Yehudah about a Get: It is not enough to put into the Get "You are hereby permitted to all men." This may still mean that he divorces her with the verbal statement, and treats the Get as a confirmation. Rather, he needs to write, "This will be for you the document of removal, bill of release, and letter of abandonment."
In other words, it does not help that we understand what the one who makes his vow wants to say. (Technically, his vow is called "partial but sufficient declaration.") This is not enough, according to Shmuel, and it must be put into words.
Incidentally, why do we pay so much attention to legalese in the case of vows? Because vows represent the power of words that existed before the Torah was given.
Art: A Legal Matter by George Fox