Transforming the Persian Capital
Being that this year is a leap year, containing two months of Adar, the 14th day of the first Adar is known as Purim Kattan, the 'small' Purim.
Until our present fixed calendar was established, the Sanhedrin (highest rabbinical court) would decide whether the year would be a leap year. They very often postponed this decision until the last minute to see if the plants had begun to sprout and there was enough time for it to grow in order to bring the Omer, as well as if the roads were dry enough for those who were travelling to Jerusalem for Passover would otherwise be unable to arrive in time for the holiday, etc. After Moshiach comes, the Sanhedrin will again decide each year whether to add a second Adar.
Likewise, there is also a Shushan Purim Kattan, a 'small' Shushan Purim, on the 15th day of the first Adar. The Jews of Shushan, the capital city of Persia, fought their enemies on the 13th and 14th of Adar and celebrated on the 15th, unlike the Jews who dwelled in other regions of the Babylonian Empire, who fought only on the 13th and celebrated on the 14th.
As there are very few customs associated with Purim Katan and Shushan Purim Katan let us take a moment to understand the significance of Shushan Purim according to Chasidut.
The celebration of this holiday was instituted in connection with the Land of Israel. Our Sages decreed that Shushan Purim be celebrated in those cities that were surrounded by walls at the time of Joshua's conquest of the Land of Israel.
In this manner, they paid respect to the Holy Land, giving its walled cities the honor given to Shushan even though they had been destroyed by the time of the Purim miracle.
However, the holiday's name is connected with a city in the Diaspora - the capital city of Achashveirosh, king of Persia (and thus the capital of the entire civilized world).
The use of the name "Shushan" expresses the completion of the Jews' mission to refine the material environment of the world. There are several levels in the fulfillment of this task; for example, the transformation of mundane objects into articles of holiness. On a deeper level, this involves the transformation into holiness of precisely those elements which previously opposed holiness.
Shushan Purim shows how Achashveirosh's capital city was transformed into a positive influence, indeed, an influence so great that it is connected with the celebration of Purim in the walled cities of Israel.
The lesson of Shushan Purim can be applied to the rest of the year. This task that we have been given, to elevate the physical into the spiritual realm, is a daily, hourly, constant assignment. Money, the truest symbol of materialism, is simply currency. But when money is given to charity, then it has been elevated to something holy.
Eating, a purely physical act, can be transformed into a spiritual act when one looks upon the act of consuming food as a means of refueling in order to have the energy to perform mitzvot.
May we use all of the extra spiritual energy given to us on Purim Katan and Shushan Purim Katan to transform the mundane into the holy and that which opposes holiness into holiness, until the whole world is transformed into a dwelling place for G-d in the Messianic Era.