We were previously taught in the Mishna (Nedarim 2:1) about certain situations when someone utters words that, though they may sound like a vow, are not formally considered to be a vow. Still, the Mishna informs us that if such a person does not fulfil what they said they would do, they have contravened the prohibition of לֹא יַחֵל (Bemidbar 30:3), i.e. the prohibition of annulling through their actions what they previously committed to do with their words.
The obvious problem is how can it be that someone has contravened the upholding of a vow if they have not, in fact, made a valid vow. The answer given in today’s daf (Nedarim 15a) is that the Mishna is referring to the rabbinic conception of לֹא יַחֵל which would apply even if someone did not make a formal vow but simply failed to do what they said they would do.
The Gemara then asks for examples where we encounter the rabbinic conception of לֹא יַחֵל. In response, the Gemara cites a Beraita which states that: ‘in the case of permitted matter that others are accustomed to treat as prohibited, you are not allowed to permit them for such people, as it says, לֹא יַחֵל – meaning ‘you shall not annul’’.
The problem with this proof, as noted by Rabbi Natan Lobart in his ‘She’erit Natan’, is that the Beraita refers to actions, not words, whereas the Gemara was seeking proof for the concept of breaking one’s words. To this he answers that when we speak of speech, we oftentimes refer to actions. In particular, among the proofs that he cites to support his point, I was particularly drawn to the Zohar’s interpretation of the words of the Shema of: וְדִבַּרְתָּ בָּם – ‘and you shall “speak” of them’, which is understood by the Zohar to refer to acting in a manner that inspires others.
Given all this, Rabbi Lobart concludes by stating that לֹא יַחֵל doesn’t just apply to words but also to actions. And this is because actions aren’t just like words. Instead, they often speak louder than words.