Short answer
Ein Sof (also spelled Eyn Sof or En Sof) is Hebrew for “without end” or “the Infinite.” In Kabbalah it names God as understood in His essence: limitless, without form, and beyond any description or thought. Everything else, including the ten sefirot and the created world, is described as coming from or being sustained by Ein Sof.
Why Kabbalah needs the concept
The Bible speaks of God in human terms, as having a hand, speaking, or being angry. Philosophers and mystics alike asked how to square this with the idea that God is infinite and unchanging. Kabbalists address the problem by distinguishing between God as He is in Himself and God as He is revealed. Ein Sof is the first, completely beyond comprehension. The second is expressed through the sefirot, which let us speak about divine qualities such as wisdom and kindness without claiming to describe the essence itself.
The term itself appears in the early Kabbalistic literature of 12th- and 13th-century Provence and Spain and became standard in the Zohar.
Ein Sof and the sefirot
A traditional picture is that Ein Sof is the source, and the sefirot are channels or vessels through which divine light is revealed. The highest sefirah, Keter, is the point closest to Ein Sof. See Chochmah and the Supernal Triad for the top of the Tree. Kabbalists are careful to say that the sefirot are not separate from God; they are the way the One is manifested.
Ein Sof and tzimtzum
How can a finite world exist if God is infinite and fills everything? The Lurianic answer is tzimtzum, “contraction” or “withdrawal.” Ein Sof is described as making room for creation, a space in which a finite world can exist. Many commentators explain tzimtzum as a metaphor, since God does not literally change location. The full story is told in Lurianic Kabbalah: Tzimtzum, the Shattering of the Vessels and Tikkun.
Is Ein Sof the same as God?
In most Kabbalistic thought, yes: Ein Sof is God at the level beyond all attributes, not a separate being above God. A few historical debates have asked whether prayer should be addressed to Ein Sof or only to the revealed aspects. Some authorities, including some who valued Kabbalah, held that prayer is directed to God as a whole and not to a particular sefirah. If you ask whether Kabbalah believes in God, the answer is yes, and Ein Sof is its most abstract way of speaking about Him.
Common misunderstandings
- Ein Sof is not impersonal “energy.” Some popular books describe it that way, but traditional sources treat it as God.
- It is not a rival to the God of the Bible. Kabbalists present it as a deeper description of the same God.
- It is not fully knowable. The Kabbalistic claim is that the Infinite cannot be grasped, only approached through its manifestations.
For more on how these ideas fit together, see The Four Worlds of Kabbalah and Kabbalah Explained.