We should thoroughly study the laws and the Chassidic discourses concerning Purim—so that we fully comprehend the material and take it to heart, thus influencing both our study and our actions.
Within a Wall or Without
The first Mishnah in tractate Megillah states that the inhabitants of cities that were fortified with a wall during the era of Yehoshua (who first led the Jews into Eretz Yisrael) read the Megillah on the 15th of Adar. In unwalled cities, large towns and villages, it is read on the 14th of Adar. This law reflects the miracle of Purim, where the Jews of Shushan (a "walled" city) were given an extra day to eradicate their enemies. The Rebbe explains the spiritual significance of the law.
Familiarity with Royalty
This is the content of our Purim service, in ascending order. At the outset of our service, we find ourselves spiritually in "unwalled cities," i.e., a state of relative spiritual "poverty"—this state is represented by the "lesser" date, the 14th of Adar… We may then be compared to "a villager who beholds the king" (who, being unaccustomed to such "revelations," is thoroughly overwhelmed), similar to the celestial vision that was seen by the Prophet Yechezkel (who was tremendously excited by the revelation). Following that, we ascend to the spiritual level of a "walled city," i.e., a state of spiritual "affluence"—this is represented by the 15th of Adar… We are then compared to a dweller of the royal capital who beholds the king (and being more familiar with royalty, is not completely overawed), similar to the same celestial vision that was seen by Yeshayah (but, being more familiar with those Heavenly realms, took it in his stride).
Touring the Heavenly Capital
The instruction we are to take from this—as it pertains to the divine service of each Jew—concerns the study of Chassidus. Chassidus speaks of the sublime Sefiros and similar topics, through which we literally fulfill the instruction to "Know the G-d of your fathers." In truth, we are all really "dwellers of the royal capital who behold the King"—so that when discussing topics such as the Ten Sefiros (and not only those of the "lowest" world of Asiyah, but even the Ten Sefiros of Atzilus), we should not feel it to be an overly unique or unfamiliar discussion. Having attained this familiarity with the Heavenly capital, we need not make any great fuss over discussing such topics; we can save our excitement for other matters… Certainly, a Jew should be excited about G-dliness—after all, that is a fundamental requirement of divine service; however, our excitement should be directed towards what transcends Atzilus.