Esther 9:27-31

9:27 Therefore, because of the account found in this letter and what they had faced in this regard and what had happened to them, the Jews established as binding on themselves, their descendants, and all who joined their company that they should observe these two days without fail, just as written and at the appropriate time on an annual basis. 9:28 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.

9:29 So Queen Esther, the daughter of Abihail, and Mordecai the Jew wrote with full authority to confirm this second letter about Purim. 9:30 Letters were sent to all the Jews in the hundred and twenty-seven provinces of the empire of Ahasuerus – words of true peace – 9:31 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.