The phrase destroy, kill, and annihilate is repeated with irony in Esther 8:11 and 9:5.
the thirteenth day of Adar, the twelfth month: Haman's "lucky day," chosen by casting lots (Esther 3:7), was eleven months after the decree. By God's plan, this gave time to overcome the decree.
The property of the Jews would be given to those who killed them. Haman cleverly bribed the potential executioners.