The meaning of the “skin of the snake”: The original cause of sin in the world was the first “snake” that convinced Chavah to eat from the Tree of Knowledge of Good and Bad. This “snake” thus represents unholiness in general. Now, even though the snake itself was unholy and brought about death etc., but when the snake dies, its skin can be used for clothing. In fact, according to one Midrash, the clothing that Hashem made for Adam and Chavah after the sin was made from the skin of the snake itself (see Targum Yonasan on Bereishis 3:21). This represents that in ‘kelipa-unholiness’ there are two aspects, the is the “body of the snake,” that is completely unholy, referred to as the “the 3 completely unholy kelipos,” and there is the “the skin of the snake,” referred to as “kelipas nogah,” that can be used for holiness, once is it separated from the completely unholy kelipos. The physical body of a Jew is called “the skin of the snake” since it is from “kelipas nogah” that can be used for holiness. However, if it is not used for holiness then it conceals holiness, since it is kelipas nogah, which is also a type of kelipa, a type of concealment on Hashem’s Light. Because the body is from kelipas nogah, ‘the skin of the snake,’ it automatically conceals Hashem’s Light to a certain extent. Because of this (and the animal soul which is also from kelipas noga) we are not automatically aware of the Elokus that is creating and enlivening us, and how we are always bound up with our Source of Life, Hashem.
Even though its not possible for limited being to see Hashem, who is infinite, but it should be possible to “see” the Elokus that is creating us, at least on some level. In addition, we should be able to know that we are still bound up in our Source in Hashem, even if we cannot “see” Him directly. In Gan Eden, the soul does “see” the Elokus creating us, and does know that it is bound up in its Source.
So why is that in this world we cannot see Elokus at all and have no idea whatsoever that we are still bound up in our Source?
This is because the world we live in is from the level of kelipas nogah, which conceals the Light of Hashem, meaning, it dulls our perception and awareness of Hashem’s Existence and how He is creating us etc.
Since the body (and the animal soul) are nourished and grow from the physical things that are kelipas nogah, therefore they are also permeated with this type of kelipah. (When the Jews received the Torah from Hashem, then needed to eat the Munn, the food from heaven, to purify their bodies from kelipas nogah, since the munn had no kelipa in it, to reach the complete awareness of Hashem in their Torah study.)
Upon considering and recognizing the truth of these facts, then one’s heart will be awakened in yearning to be bound up with this idea and bring it into his conscious awareness throughout the entire day, so that he should never be separated from it at all.
This is the concept of “acceptance of the Sovereignty of Hashem who is in Heaven” in the first verse of Krias Shema.
In the Gemara (Brachos 13a) it says that the first parsha of Shema is about “accepting Hashem’s Sovereignty.” The simple meaning of this is that when we say that “Hashem is our G-d, Hashem is One,” this means that since He is our one and only G-d, He is also our True King who we worship and serve with unconditional commitment. Even if a human king would tell us to do something against Hashem’s will, we would not listen to him, since Hashem is the One and only Supreme Being that His commands supersede any else’s.