In these chapters, the Rebbe Rashab explains that this same dynamic — the functioning of Chochmah and Binah and the synergy between them — applies on an even higher spiritual plane. He introduces certain fundamental Kabbalistic concepts, beginning with a description of G‑d’s infinite light that existed before all creation. As previously explained, if a mashpia would convey the full scope of what he has to offer as it exists within itself, the recipient would be unable to absorb it. Similarly, were G‑d’s light to be revealed in its innate state, creation would be impossible. Therefore, a tzimtzum, a withdrawal of that light and its concentration into a single point, was necessary. However, as an undefined entity, that point still constituted a state of Divine concealment; in order that it should be revealed, a further process of expanding and developing it was necessary.
The Rebbe Rashab explains the process of revelation in those lofty mystical realms by using the geometrical terms — point, line, and area. The tzimtzum involves the withdrawal of G‑d’s light into a single point (parallel to the yud). From that point shines forth the kav, a vector, i.e., line of Divine light (parallel to the vav), which creates an area (parallel to the hei), i.e., the framework of existence that exists after the tzimtzum and ultimately results in the creation of our world.
The synergistic interrelation between the forces of revelation and tzimtzum is brought about by the essence of G‑d’s infinite light, which transcends both concealment and revelation.
