Rebbe Nachman on Purim
Our joy and clapping and dancing on Purim make us worthy of receiving the Torah in its two aspects, revealed and hidden. For the great revelation that came about through Mordechai and Esther was "receiving the Torah." Through this we are able to fulfill the mitzvah of counting the Omer the proper way. The kelipah of Haman the Amalekite (may his name be blotted out) is crushed. The force of pride, idolatry and atheism is broken. Great faith, holy wisdom and true life and length of days are brought into the world. The severity of God's harsh judgments is sweetened, and all the harsh decrees against Israel are revoked (Likutey Eitzot 10:8).
Purim is a preparation for Peach. Through the mitzvah of Purim, we are protected from chametz on Pesach (Likutey Moharan II, 74).