Baal HaSulam, ‘Introduction to The Book of Zohar,” Item 9: And the only difference between the souls and His essence is that the souls are a part of His essence. This means that the amount of Light that they receive in their Kli, being the will to receive, is already separated from the Creator, as it is predicated on the disparity of form of the will to receive. And this disparity of form made it a part by which they were separated from the “whole” and became a “part.” Thus, the only difference between them is that one is a “whole” and the other is a “part,” as a stone that is carved from a mountain.
Now we are in a space with myriad waves and radiations of different frequencies that cover the whole space from zero to infinity. We perceive these waves with the help of different receivers, which can be tuned to these waves and perceive them. The receiver perceives the wave according to the equivalence with the wave, which means that the receiver creates a certain wave that is a replica of the wave on the outside and then they enter one another and create a resonance, which means that they connect. I perceive this connection and feel whether, for example, it is a radio wave that I can hear or whether it is the range of a television wave that I can see.
Thus, I perceive the “wave” of the general soul, since all of creation is a soul, a spiritual vessel that is totally filled by the Light, by Malchut of Ein Sof (Infinity). When I am external to it, I only have a small “sensor,” a spark that I have received and that I have to develop now in order to perceive wave after wave. Thus I create and develop the “receiver,” and by it, I perceive part of the “whole” that I am in, part of my soul. Generally speaking, all the space of Malchut is my soul, which I am going to acquire. But I discover this gradually to the extent that I develop my “receiver,” my vessels of perception. So it turns out that it is me who separates the part from the whole according to my currently corrected attributes.
From the 4th part of the Daily Kabbalah Lesson 3/4/13,”Introduction to The Book of Zohar”