Esther 9:30-31

And he sent letters to all the Jews in the hundred and twenty-seven divisions of the kingdom of Ahasuerus, with true words of peace, Giving the force of law to these days of Purim at their fixed times, as they had been ordered by Mordecai the Jew and Esther the queen, and in keeping with the rules they had made for themselves and their seed, in connection with their time of going without food and their cry for help.