Esther 8:12 (ESV)

12 on one day throughout all the provinces of King Ahasuerus, on the thirteenth day of the twelfth month, which is the month of Adar.

The second edict also contained the same date as that of the first edict: the thirteenth of the month of Adar. Again, Mordecai did not want the Jews to fight more than what was necessary. This was not a matter of revenge, but of just self-defence.