Where does "minhag avoseinu byadeinu" as a halachik concept, which is commonly cited as the source for keeping two days of yom tov outside of Israel, originate from?

  • Do you mean the Gemara that mentions it, or the source upon which the letter cited in that Gemara is based?
    – Seth J
    Commented Oct 16, 2012 at 16:31
  • @SethJ maybe you can help me rephrase. my question is not where does the gemarah say it but what is the source for applying it as a halachic concept. meaning why, just because it used to be done, do we not change? Why do we ignore all the halachic issues that come along with those changes etc.?
    – user1668
    Commented Oct 16, 2012 at 17:12
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    Since an adequate answer has been provided to the question as written, perhaps you should write your intended question as a stand-alone one.
    – Seth J
    Commented Oct 16, 2012 at 18:27
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    I agree with @SethJ . See also meta.judaism.stackexchange.com/q/1229/759
    – Double AA
    Commented Oct 16, 2012 at 18:31
  • @PM, how about something like "Why does the Gemara (Beitzah 4b) state that we need to follow our forefathers' custom with regard to keeping two days of Yom Tov, even though we know the dates now with our fixed calendar?"
    – Seth J
    Commented Oct 16, 2012 at 18:53

1 Answer 1


Gemora Beitzah 4b, actually talking about two days yom tov

והשתא דידעינן בקביעא דירחא מאי טעמא עבדינן תרי יומי משום דשלחו מתם הזהרו במנהג אבותיכם בידיכם

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    It seems he meant to ask a different question. I think, though, that you should keep your answer here, because it answers the question as it was written, and that he can ask a separate question that focuses on what he intended to originally.
    – Seth J
    Commented Oct 16, 2012 at 18:28
  • Let's not forget the next words of the gemara זמנין דגזרו המלכות גזרה ואתי לאקלקולי
    – Double AA
    Commented Dec 24, 2012 at 17:05

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