Present, the Jews keep three days - the 13th, the 14th, and the 15th of Adar - as connected with “the Feast of Purim;” but they make the 13th a fast, commemorative of the fast of Esther Esther 4:16, and keep the feast itself on the 14th and 15th of Adar.
Related Commentaries of Esther 3:13
Esther 3:13
13 And the letters were sent by posts into all the king's provinces, to destroy, to kill, and to cause to perish, all Jews, both young and old, little children and women, in one day, even upon the thirteenth day of the twelfth month, which is the month Adar, and to take the spoil of them for a prey.