Kabbalah (to receive) - The Hidden Torah - the core, essence and spirituality of Torah Judaism handed down orally from generation to generation. Wrote down for the first time by Shimon bar Yochai in a book called the Zohar which means "splendor" or "radiance."
In the beginning of G-d's creating the heavens and the earth - when the earth was profoundly empty with darkness over the face of depths, the Divine Presence hovered upon the face of the waters. G-d said, "Let there be light!" and there was light. (Bereishit 1:1)
Originally, there was only Ain Sof, the Infinite - all of reality was G-d.
In order for the universe to exist, G-d had to "withdraw" from some part of that reality.
This metaphorical withdrawal (tzimtzum) left a "place" bereft of G-d's Presence, allowing the cosmos to come into being.
Not forsaking this empty space, G-d projected a beam of light which became a mass without form inside that space. From that mass, all levels of reality came into existence.
G-d then injected another beam of light, which began to create "vessels"; these represent facets of G-d's activity and G-d's qualities, each containing a portion of that light from Ain Sof.
This process could not reach completion and was halted. Some of the vessels were not strong enough to contain the divine light. These vessels were shattered into bits.
As the vessels fell and became the world of reality and material and this ray of light returned to Ain Sof. A residue of the divine light adhered to the shattered vessels as oil adheres to a vessel even after it is poured out.
Thus there are sparks of G-d's light trapped in every piece of reality.
G-d left an "imperfect unity" of his own creation. Through prayer and correct action, a person liberates and elevates these sparks and "repairs" G-d's unity, so to speak. That process is known as Tikkun Olam (repair of the world). (Rabbi Yitzchak Luria - "The Arizal" - Talmudist and Kabbalist par excellence 16th Century)
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Kabbalah Trees :
Kabbalistic Priestly Blessing (Birkat Kohanim):