Esther 3:5-7

When Haman saw for himself that Mordecai didn’t bow down and kneel before him, he was outraged. Meanwhile, having learned that Mordecai was a Jew, Haman hated to waste his fury on just one Jew; he looked for a way to eliminate not just Mordecai but all Jews throughout the whole kingdom of Xerxes. In the first month, the month of Nisan, of the twelfth year of Xerxes, the pur—that is, the lot—was cast under Haman’s charge to determine the propitious day and month. The lot turned up the thirteenth day of the twelfth month, which is the month of Adar.