Esther 3:5-7

When Haman saw that Mordecai did not bow or pay him homage, Haman was filled with wrath. But he disdained to lay hands on Mordecai alone, for they had told him of the people of Mordecai. Instead, Haman sought to destroy all the Jews who were throughout the whole kingdom of Ahasuerus—the people of Mordecai. In the first month, which is the month of Nisan, in the twelfth year of King Ahasuerus, they cast Pur (that is, the lot), before Haman to determine the day and the month, until it fell on the twelfth month, which is the month of Adar.