Esther 9:20-28

Then Mordecai recorded these events, and he sent letters to all the Jews who were in all the provinces of King Ahasuerus, both near and far, obliging them to celebrate the fourteenth day of the month Adar, and the fifteenth day of the same month, annually, because on those days the Jews rid themselves of their enemies, and it was a month which was turned for them from sorrow into gladness and from mourning into a holiday; that they should make them days of feasting and rejoicing and sending portions of food to one another and gifts to the poor. Thus the Jews undertook what they had started to do, and what Mordecai had written to them. For Haman the son of Hammedatha, the Agagite, the adversary of all the Jews, had schemed against the Jews to destroy them and had cast Pur, that is the lot, to disturb them and destroy them. But when it came to the king’s attention, he commanded by letter that his wicked scheme which he had devised against the Jews, should return on his own head and that he and his sons should be hanged on the gallows. Therefore they called these days Purim after the name of Pur. And because of the instructions in this letter, both what they had seen in this regard and what had happened to them, the Jews established and made a custom for themselves and for their descendants and for all those who allied themselves with them, so that they would not fail to celebrate these two days according to their regulation and according to their appointed time annually. So these days were to be remembered and celebrated throughout every generation, every family, every province and every city; and these days of Purim were not to fail from among the Jews, or their memory fade from their descendants.