Esther 9:20-28

Now Mordecai recorded these events, and he sent letters to all the Jews who lived in all the provinces of King Ahasuerus, both near and far, obliging them to celebrate the fourteenth day of the month of Adar, and the fifteenth day of the same month, annually, because on those days the Jews rid themselves of their enemies, and as the month which was turned for them from grief to joy and from mourning into a holiday; that they should make them days of feasting and rejoicing and sending choice portions of food to one another and gifts to the poor. So 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 enemy of all the Jews, had plotted against the Jews to destroy them and had cast Pur, that is, the lot, [to find the right time] to disturb and destroy them. But when it came before the king, he commanded in writing that Haman’s wicked scheme which he had devised against the Jews was to return on his own head, and that he and his sons should [endure what he planned for the Jews and] be hanged on the gallows. Therefore they called these days Purim after the name Pur (lot). And because of all the instructions in this letter, and what they had faced in this regard and what had happened to them, the Jews established and made it a custom for themselves and for their descendants and for all who joined them, so that they would not fail to celebrate these two days as it was written and at the 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 cease from among the Jews, nor their memory fade from their descendants.