Esther 9:25-27

New Revised Standard Version, Anglicised Catholic Edition

²⁵ but when Esther came before the king, he gave orders in writing that the wicked plot that he had devised against the Jews should come upon his own head, and that he and his sons should be hanged on the gallows. ²⁶ Therefore these days are called Purim, from the word Pur. Thus because of all that was written in this letter, and of what they had faced in this matter, and of what had happened to them, ²⁷ the Jews established and accepted as a custom for themselves and their descendants and all who joined them, that without fail they would continue to observe these two days every year, as it was written and at the time appointed.