Esther 9:20-28 CSB
Mordecai recorded these events and sent letters to all the Jews in all of King Ahasuerus’s provinces, both near and far. He ordered them to celebrate the fourteenth and fifteenth days of the month of Adar every year because during those days the Jews gained relief from their enemies. That was the month when their sorrow was turned into rejoicing and their mourning into a holiday. They were to be days of feasting, rejoicing, and of sending gifts to one another and to the poor.
So the Jews agreed to continue the practice they had begun, as Mordecai had written them to do. For Haman son of Hammedatha the Agagite, the enemy of all the Jews, had plotted against the Jews to destroy them. He cast the pur — that is, the lot — to crush and destroy them. But when the matter was brought before the king, he commanded by letter that the evil plan Haman had devised against the Jews return on his own head and that he should be hanged with his sons on the gallows. For this reason these days are called Purim, from the word pur . Because of all the instructions in this letter as well as what they had witnessed and what had happened to them, the Jews bound themselves, their descendants, and all who joined with them to a commitment that they would not fail to celebrate these two days each and every year according to the written instructions and according to the time appointed. These days are remembered and celebrated by every generation, family, province, and city, so that these days of Purim will not lose their significance in Jewish life and their memory will not fade from their descendants.
CSB: Christian Standard Bible