TSK · Esther 9:21

In the first month, which is the month Nisan, in the twelfth year of King Ahasuerus, they cast Pur, that is, the lot, before Haman from day to day, and from month to month, and chose the twelfth month, which is the month Adar.

But the Jews who were in Shushan assembled together on the thirteenth and on the fourteenth days of the month; and on the fifteenth day of that month, they rested, and made it a day of feasting and gladness.