“Had I known that…” (אִילּוּ הָיִיתִי יוֹדֵעַ שֶׁ…). These are the words used in today’s daf (Nedarim 26a) which discusses the laws pertaining to נִדְרֵי שְׁגָגוֹת (unintentional vows) where a person made a vow restricting themselves from benefitting from a group of people or items but didn’t realize that their vow included people or items that they didn’t mean to restrict themselves from. In such a situation, the claim that “had they known that…” (אִילּוּ הָיִיתִי יוֹדֵעַ שֶׁ..) the group of people or items included in their vow unintentionally included those they didn’t mean to include subsequently releases them from their vow.
Interestingly, and looking beyond the laws of vows, there are numerous areas of Jewish law when a similar claim of “had I known that…” (אִילּוּ הָיִיתִי יוֹדֵעַ שֶׁ…) is effective to reverse an agreement or decision on the basis of what we call מֶקַּח טָעוּת. However, in contrast to the laws of vows, in most other cases it often takes some time for a person to realize that they have been misled or have made a mistake. Moreover, whereas vows, which are ultimately commitments we make to ourselves, are often released, there is unfortunately a general reluctance, for reasons not entirely clear, to dissolve other agreements or relationships on the basis of מֶקַּח טָעוּת.
What this means is that while “Had I known that…” (אִילּוּ הָיִיתִי יוֹדֵעַ שֶׁ…) may well be words that we say to ourselves about many matters, they are only effective in reversing erroneous decisions in some aspects of life, whereas in other situations, we are often expected to live with the mistake we made.
What all this leads to is two important facts. Firstly, before making significant life decisions, we should do our due diligence and try and find out as much as we can about what we are about to commit to. And secondly, if someone we know is about to make a significant life decision, and we have information that may prompt them at a later stage to say to themselves “Had I known that…” (אִילּוּ הָיִיתִי יוֹדֵעַ שֶׁ…), then we should share this information with them now.
Ultimately, while the laws of vows found in Massechet Nedarim may be complex, the solutions offered in Massechet Nedarim to errors made when making vows are often more easily available than solutions to other errors that we may make in life. Given this, we should all do what we can to avoid situations when we or others come to say, “Had I known that…” (אִילּוּ הָיִיתִי יוֹדֵעַ שֶׁ…).