TSK · Esther 9:17

So the royal scribes were summoned in the first month, on the thirteenth day of the month. Everything Haman commanded was written to the king’s satraps and governors who were in every province and to the officials of every people, province by province according to its script and people by people according to its language. In the name of King Ahasuerus it was written and sealed with the king’s signet ring.

The Jews Prevail over Their Enemies In the twelfth month(that is, the month of Adar), on its thirteenth day, the edict of the king and his law were to be executed. It was on this day that the enemies of the Jews had supposed that they would gain power over them. But contrary to expectations, the Jews gained power over their enemies.

to have them observe the fourteenth and the fifteenth day of the month of Adar each year