Adar started between Sunday and Monday nights {The Jewish month begins on the New moon}.
Our sages have taught that when Adar starts we are to increase our joy. One may ask how can the Torah demand us to be joyous during the entire month period? A person must do his best effort to remain happy and joyous throughout the month. One of the reasons given for the joyous nature of Adar is the fact that Purim occurs in the middle of the month. Purim is a time of happiness for we remember how Hashem saved us from the brink of annihilation at the hands of Haman. Purim is a time for doing a little drinking, dressing up and dressing the children up in costumes, and a time for funny skits {called Purim Shpiels}.
http://www.torah.org/learning/yomtov/purim/5757/vol2no28.htmlThe Month of Adar
A Month of Happiness
by Rabbi Yehudah Prero
This year being a Jewish leap year, the second month of Adar begins on Sunday night, March 9, 1997. The Gemora (Ta'anis 29a) tells us that "Just as from when the month of Av enters, we minimize our happiness, so too from when the month of Adar enters, we increase our happiness."
The K'sav Sofer explains the connection and comparison that the Gemora makes between these two months. In the month of Av, both of our holy temples were destroyed. The nation of Israel was exiled in Av. Many horrific tragedies befell the Jewish people in the month of Av. For this reason, Av is always a month of sadness. Even in times when Jews are not oppressed and they can practice their religion without any hindrance, the month of Av remains a month of sadness. In Av, we minimize our happiness not because we are mourning our physical state in exile. We minimize our happiness because we recognize the pain and suffering that our souls experience because we are in exile.
In Adar, the nation of Israel was saved from annihilation. Jews who lived throughout the empire of Achashverosh were faced with certain death. Through a miraculous turn of events, this threat was removed and the Jews were saved. There was celebration everywhere. The Jews at this time renewed their commitment to observing the Torah. It was a time of overwhelming happiness. During the month of Adar, we do not rejoice because we were physically saved from death. We rejoice because our souls experienced a redemption: the Jews were threatened with death as a punishment for their sins, and because they repented, they were saved. The Jews did not only repent for their sins; they raised their commitment to G-d and the Torah to new levels. It is for this spiritual redemption that we celebrate throughout the entire month of Adar. Just as in Av, when we mourn because of our spiritual loss, we celebrate in Adar because of our spiritual gain.
The Chasam Sofer notes that the law "When Av enters we minimize our happiness" is codified by the Rambam in his Mishneh Torah. However, the law "When Adar enters we increase our happiness" is not mentioned. The reason for this, Rabbi Sofer explains, is that in Av, there are physical manifestations of our mourning. One can not conduct weddings, and one cannot build or plant for certain festive purposes. These actions can be codified. The increase in happiness we are to experience during Adar has no mandated manifestation. We are supposed to feel a great happiness in our hearts during the month of Adar. This is the extent of the law, and this call to increase our feelings of joy can not be codified.
During the month of Adar, we should all strive to feel this happiness. It should truly be a month of joy for all and for all time!