Esther’s command established these matters of Purim, and the matter was officially recorded. ¹ 

For this reason these days are known as Purim, after the name of pur.

For Haman the son of Hammedatha, the Agagite, the enemy of all the Jews, had devised plans against the Jews to destroy them. He had cast pur (that is, the lot) in order to afflict and destroy them.

So Queen Esther, the daughter of Abihail, and Mordecai the Jew wrote with full authority to confirm this second ¹  letter about Purim.

In the first month (that is, the month of Nisan), in the twelfth year ¹  of King Ahasuerus’ reign, pur ²  (that is, the lot) was cast before Haman in order to determine a day and a month. ³  It turned out to be the twelfth month (that is, the month of Adar). ⁴ 

These days were to be remembered and to be celebrated in every generation and in every family, every province, and every city. The Jews were not to fail to observe these days of Purim; the remembrance of them was not to cease among their descendants.

to establish these days of Purim in their proper times, just as Mordecai the Jew and Queen Esther had established, and just as they had established both for themselves and their descendants, matters pertaining to fasting and lamentation.