Esther 9:24-26

24Haman son of Hammedatha the Agagite, the enemy of the Jews, had plotted to crush and destroy them on the date determined by casting lots (the lots were called purim).

25But when Esther came before the king, he issued a decree causing Haman’s evil plot to backfire, and Haman and his sons were impaled on a sharpened pole.

26That is why this celebration is called Purim, because it is the ancient word for casting lots. So because of Mordecai’s letter and because of what they had experienced,