Monday, May 28, 2018

calendar - Why is Rosh Hashana two days in Jerusalem?


Rosh Hashana is the only festival celebrated for two days even in Jerusalem, since there was a possibility that witnesses for the new moon would come in the middle of the day and the Beis Din would declare it Rosh Hashana (retroactively). If the witnesses didn't come, Rosh Hashana would (biblically) automatically be deferred to the next day, but Melacha would continue being prohibited due to the fear that people would Mezalzel the first day of Rosh Hashana the next year.


Nowadays, Rosh Hashana always falls out on the 1st and 2nd. So the calendar is programmed "as if" the witnesses came the first day.


Why do we have a second day?




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