Esther 3:5-7

When Haman saw that Mordecai would not kneel down or pay him honour, he was enraged. Yet having learned who Mordecai’s people were, he scorned the idea of killing only Mordecai. Instead Haman looked for a way to destroy all Mordecai’s people, the Jews, throughout the whole kingdom of Xerxes. In the twelfth year of King Xerxes, in the first month, the month of Nisan, the pur (that is, the lot) was cast in the presence of Haman to select a day and month. And the lot fell on the twelfth month, the month of Adar.