What is the Tzimtzum, on what level did the Tzimtzum take place, and why was it needed?^[1]

The Tzimtzum occurred within the infinite light of G-d, the Or Ein Sof. In this level, the Tzimtzum involved the infinite light of G-d becoming reincorporated in the luminary, the essence of G-d. The reason for this is because the world’s and its creations are not able to receive from a revelation of the infinite light of G-d as it exists from G-d’s essence. If they were to receive from it, they would never become independent entities as they would be completely nullified in their existence to G-d. For this reason, G-d contracted the light so that it be incorporated within the luminary and exist only in the potential and not in the actual. This caused the infinite light of G-d to become concealed and hence only the luminary itself, which is the essence of G-d, remained consciously revealed.

Was there a Tzimtzum of the essence of G-d? Within the luminary, which is the infinite being of G-d himself, contraction or concealment is not a possibility heaven forbid. On the contrary, the luminary is always revealed and hence even children know that there is a G-d that is found even though they do not comprehend the details of this G-d being that they do not have a revelation of its light. Thus, there is no difference between how the luminary is found below versus above. Now, although earlier we spoke of an empty space that was created as a result of the contraction, this refers only to G-d’s infinite light and not to the essence of G-d.

[1] Torah Or p. 14a