"Meanwhile, the remainder of the Jews who were in the king's provinces also assembled to protect themselves and get relief from their enemies. They killed seventy-five thousand of them but did not lay hands on the plunder. This happened on the thirteenth day of the month of Adar, and on the fourteenth they rested and made it a day of feasting and joy." NIV translation
The Jews outside of Susa celebrated after the day of their deliverance while the Jews in Susa were having their day of vengeance.
"The Jews in Susa, however, had assembled on the thirteenth and fourteenth, and then on the fifteenth they rested and made it a day of feasting and joy. That is why rural Jews - those living in villages - observe the fourteenth of the month of Adar as a day of joy and feasting, a day for giving presents to each other." NIV translation
Purim is celebrated even today and there is a difference in the day of celebration depending on where the Jew lives. No matter what day it is celebrated on it is still a day to remember the deliverance of God.
We, as Christians, should take every day to remember how God has delivered us from sin and death through Jesus Christ. As the Jews gave presents to each other, we should give the good news of Jesus to all we meet.
"Mordecai recorded these events, and he sent letters to all the Jews throughout the provinces of King Xerxes, near and far, to have them celebrate annually the fourteenth and fifteenth days of the month of Adar as the time when the Jews got relief from their enemies, and as the month when their sorrow was turned into joy and their mourning into a day of celebration. He wrote them to observe the days as days of feasting and joy and giving presents of food and gifts to the poor." NIV translation
Mordecai sent letters to all of the Jews establishing Purim as an annual holiday. The purpose was for the people to take time to remember what God had done for them in delivering them from their enemies. In our world today it seems like we have holidays for everything that we can imagine but most of them are not set aside for remembering the things of the Lord.