We will begin to shed some light on the subject by first delving into the profound teaching of the Bnei Yissaschar (Adar 2, 7). He provides us with a novel, practical explanation for the mitzvah of “MAchatzis hashekel.” In fact, it is the basis for the majority of the teachings of the sefer Tanya in Likutei Amarim. Its source is the sacred teachings of our illustrious teacher, the Arizal, in Eitz Chaim (Sha’ar 49). There he interprets the prophetic vision of Yechezkel HaNavi (Yechezkel 1, 4): "וארא והנה רוח סערה באה מן הצפון ענן גדול ואש מתלקחת, ונוגה לו סביב, ומתוכה כעין החשמל מתוך האש." I saw and behold! There was a stormy wind coming from the north, a great cloud with flashing fire and a “nogah” (brilliance) surrounding it; and from its midst like the color of the “chashmal” from the midst of the fire.
The Arizal teaches us that HKB”H showed Yechezkel HaNavi in this vision how the holy Shechinah—described here as “like the color of ‘chashmal’ from the midst of the fire”—is surrounded by four klipos. They are analogous to the klipos—peels or shells—that envelop a fruit. Thus, every Jew that longs to connect with HKB”H must peel away those klipos, one layer at a time, to reach and reveal the holy Shechinah that is the root of all the forms of kedushah that HKB”H displays in the world.
Initially, Yechezkel saw three harsh klipos: (1) a stormy wind, (2) a great cloud, and (3) a flashing fire. They were followed by a fourth klipah called “nogah,” which represents an intermediate stage (dimension) between the first three klipos and the holy Shechinah.
Let us elaborate. The first three klipos are “temeiot”—impure and unholy; they are totally devoid of good; they are pure evil. They are the sustaining force of the nations of the world, all the prohibited foods, and all the things prohibited by the Torah. Anyone who eats such foods or transgresses, doing that which the Torah has prohibited, attaches themselves to these three harsh, unholy klipos. The only way to cleanse oneself of them is to perform teshuvah based on ahavah, which transforms intentional sins to merits. Failure to perform this sort of teshuvah during one’s lifetime requires postmortem cleansing in the fires of Gehinnom, which incinerates all traces of evil attached to the neshamah.
In contrast, the fourth klipah, klipat “nogah,” is comprised of both good and bad, akin to the “Eitz HaDa’as Tov VaRa.” It surrounds the Shechinah creating a barrier between the Shechinah and the three klipos “temeiot.” Its external half, which faces the three unholy klipos is totally evil, whereas its internal half, which faces the Shechinah is totally good. This explains its appellation “klipat nogah.” For, with regards to its evil, negative half, it is called a “klipah”; yet, with regards to its good, positive half, it is called “nogah,” which means a brilliant light.
Now, the sustaining-force of the animalistic soul—which is present in the left cavity of every Jew’s heart—and the sustaining-force of everything that is permitted by Torah-law, stems from the klipah of “nogah,” which is an amalgamation of good and evil. In addition, however, every Jew also has a neshamah in their brain, which is entirely holy devoid of any trace of evil. This is the meaning of what we say every morning in Birchot HaShachar: "אלקי נשמה שנתת בי טהורה היא"—my G-d, the neshamah You placed within me is pure. Thus, it is the sacred duty of every Jew to thoroughly separate the good portion of klipat “nogah” from its evil portion and elevate it to serve Hashem exclusively.
