Esther 9:31-32

Amplified Bible

³¹ to establish these days of Purim [to be observed] at their appointed times, just as Mordecai the Jew and Queen Esther had established for them, and as they had established for themselves and for their descendants with instructions regarding their times of fasting and their lamentations (expressions of needing help). ³² The command of Esther established these customs for Purim, and it was written in the book [of the royal archives].