The focus of the celebrations was not so much the Jews’ victory in battle, but rather the relief from their enemies, with which God had once again blessed them (see comments under Esther 9:16).
For more than half a year, the month of Adar had an ominous sound when it was mentioned among the Jews. Yet now this month became a month of joy and festivity. What were initially spontaneous celebrations were now to become a fixed tradition.
22 as the days on which the Jews got relief from their enemies, and as the month that had been turned for them from sorrow into gladness and from mourning into a holiday; that they should make them days of feasting and gladness, days for sending gifts of food to one another and gifts to the poor.