This week is Shabbos Shekalim. This parsha speaks about bringing a half shekel to the Bais Hamikdosh. On Rosh Chodesh Adar it was announced that everyone should bring their Machatzis HaShekel and on the fifteenth of Adar the collection began; so by the time it was Rosh Chodesh Nisan the funds would be amassed for the purchase of the communal sacrifice. On Rosh Chodesh Nissan they would bring the community sacrifices which had been acquired with the recently collected shekolim contributed by Bnei Yisrael. For this reason on Shabbos Mevorchim Adar we read for Maftir the parsha which speaks about Machatzis HaShekel.
The question is asked, why is only a half shekel given? Why not a complete shekel? Additionally, the Torah says that twenty gerah is a shekel, give half; since ten is a complete number, why does it not say give ten gerah? The Talmud Yerushalmi states that Moshe didn't know what Machatzis HaShekel is – so Hashem took out a fiery half shekel from under his Kisei Hakavod (Throne of Glory) and said _this_ is what you are going to give. How is it that Moshe Rabbenu couldn't figure this out?
The explanation is that the Machatzis HaShekel was an atonement for the Cheit Ha'eigel (sin of the Golden Calf). Moshe Rabbenu's question was how could a half shekel forgive the Cheit Ha'eigel? Hashem showed Moshe Rabbenu that in the coin that a Jew gives there is fire – the essence of the neshoma of a Jew which is carved out from under the Kisei Hakovod.
On a superficial level it appears as if we are forcing him to give a half shekel but deep down he is doing it because his neshoma, which has a burning love for Hashem, wants to do that mitzvah. That's why it is a half shekel. How is this an atonement? When a Jew knows that he is only half and his other half is Hashem and he unites himself with Hashem, the Jew's ten powers of the neshoma unite with the ten sifiros of Hashem and become one shekel - one being. The Jew removes himself from the sin of the eigel and he reveals his essence - the Yechidah - the part of the neshoma that is one with Hashem for there sin never touched and from there forgiveness comes.
The point is (a) that even if a Jew is forced to do a mitzvah and it appears to be a superficial act, the neshoma is burning with love for Hashem, and (b) that a Jew is only half and by connecting to another Jew he completes a shekel; this is the mitzvah of Ahavas Yisroel. The lesson for us is that even if a person is rich, whether spiritually or physically, he needs to know that he is only half, and even if one is poor, he should not feel that he is nothing; because the contribution of the rich cannot be complete without the contribution of the poor.
There is a saying told in the name of the Tzemach Tzedek that the word מחצית shows that a person has to be connected to a Tzadik. There are five letters in the word מחצית. The צ is in the middle of the word and near it, on either side, are ח and י spelling חי (life) and on the outside of the word, are מ and ת, meaning the opposite of life. Hence, to be truly alive one must be connected to the Tzadik.