Power of Court

Parshat אמור has a long section discussing the holidays. The dates of these holidays are determined by the בית דין.

They determine whether a month is twenty nine or thirty days, and whether or not there will be an extra month of Adar.

One rabbi put it in an interesting manner. It is the בית דין that decides whether we will be eating Hamentashen on Purim or Matza on Pesach. This depends if an extra Adar is added.

Despite the holiness of Yom Kippur and other festivals, we apply the principle of בית דין של מטה גוזר, בית דין של מעלה מקיים, that the court on earth decrees, and the court in Heaven fulfills.