Shiluach Hat'mai'im min hamachneh:

Tzav es B'nei Yisrael vishalchu min hamachaneh kol tzaruah vechol zav vechol tameh lanefesh..
"Command B'nei Yisrael that they send out of the camp everyone with tzara'as, and everyone that has an issue, and everyone that is tameh, unclean for coming in contact with the dead."

The metzorah was sent out of all three camps; Machaneh Shechinah, Machaneh Levi'ah and Machaneh Yisrael.
The zav was sent out of two camps; Machaneh Shechinah and Machaneh Levi'ah.
The tameh lanefesh was sent only out of Machaneh Shechinah.

The tzaruah is representative of ga'avah, arrogance and anger, for tzara'as comes where there is lashon harah, evil speech.
The zav is representative of ta'avah, indulgence in desire.
The tameh lanefesh is representative of atzvus or despondency.

The arrogant tzaruah was sent out of the entire camp, out of all three boundaries, for ga'avah, arrogance and anger, have no place at all in Am Yisrael.  Hashem says about the arrogant that "I and he cannot dwell together in the same place."

The zav was sent out of the two camps, Machaneh Shechinah and Machaneh Levi'ah.  Machaneh Levi'ah was the camp designated for Shaivet Levi.  This tribe devote their lives to learning, teaching and disseminating Torah.  In this capacity, of Talmid Chacham, the indulgence in desire is inappropriate.

The tam'eh lanefesh was only sent out of Machaneh Shechinah.  Sometimes one can even find the Talmid Chacham despondent.  However, the tam'eh lanefesh is sent out of Machaneh Shechinah, for in the boundary of the Shechinah, there can only be joy, Oz v'chedvah bim'komo, "Strength and joy is to be found in His Place."

We are taught that atzvus, depression and despondency,  is the strongest Klippah, obstruction to Kedusha, holiness.  Thus, we find that idolatry is called by a similar name.  (etzev=sadness, atzavim=idols)  A person gets depressed when he feels shortcoming, or something lacking in his life.  But when a person responds to this feeling with atzvus, it is most self defeating.  Think about it!  The Shechina is the Source of all blessing, of all bounty, of all the good things and solutions that we could all imagine (or can't imagine) in our most ambitious and greatest dreams.  When a person is chas veshalom despondent, he cannot be attached to the Shechina, so he is in effect, denying himself access to the very solution to all his problems, the fulfilment of  all his frustrated aspirations!

It is not easy, for the Yetzer Harah, through the senses, dictates exactly the contrary. In this sense, there is a strong parallel between despondency and the description of idols: "they have mouths but they cannot speak, they have eyes but they cannot see.."  It is a response to a predicament, that seems to gratify, but is most empty, blocked off and powerless.

This is what makes simcha, joy,  such a great and rewarding challenge.  It is even worth making the motions of being joyful, "putting on a show".  It works, if we do it with the right intention.  It is not false.  We are simply exerting ourselves to seek out the Shechinah.  It is therefore of utmost importance for a Jew never to speak pessimistically or cynically or grouchily.  Also, it is a most important spiritual exercise to THINK positive thoughts, and to focus on all the blessings in our lives and how HaKadosh Baruch Hu at every moment , and also at this present moment is tending to all of our extensive and intricate needs.

Atzvus is the cause of all malady..
Simcha is the cure for everything.
 

May we all merit to receive the Torah with great Simchah.

Chag Same'ach and
A gutten Erev Shabbos,

from Yerushalayim Ir haKodesh.