Short answer. Ein Sof (אֵין סוֹף, "Without-End" / "the Infinite") is the Kabbalistic name for God as utterly hidden: beyond every attribute, name, and even the word "God." It is not the personal Lord of scripture; that Lord is reached only through the ten Sefirot, the emanated powers through which the Infinite becomes knowable. Ein Sof itself is unsayable, an apophatic limit rather than an object of worship.
"Without-End": a name that refuses to be a name
The Hebrew Ein Sof literally negates: ein ("there is not") plus sof ("end" or "limit"). It is a phrase that withholds rather than describes: closer to "the Limitless" than to a title. Gershom Scholem, who founded the modern academic study of Kabbalah, stressed that Ein Sof denotes the divine as it is in itself, prior to any self-disclosure, and that the term entered Kabbalistic usage in the late twelfth and thirteenth centuries among the circles around the Sefer ha-Bahir and the Provençal-Catalan mystics (Scholem, Major Trends in Jewish Mysticism, 1941). Crucially, Ein Sof appears nowhere in the Hebrew Bible; it is a reconstructed theological category built to name what scripture leaves unnamed. The very grammar is apophatic, a via negativa in two words. To say anything positive about Ein Sof (that it is "good," "one," "merciful") is already, on this view, to have stopped speaking about Ein Sof and started speaking about its effects. The name is engineered to fail as a description, and that failure is the point: it marks the horizon past which language cannot follow.
The Sefirot: how the Infinite becomes a God you can address
If Ein Sof is unnameable, how does Kabbalah have so much to say about God? Through the Sefirot, the ten emanations (Keter, Hokhmah, Binah, Hesed, Gevurah, Tiferet, Netzah, Hod, Yesod, Malkhut) that flow out of the Infinite like light through a graded series of vessels. The classic source is the Zohar (late-13th-century Castile, traditionally ascribed to Shimon bar Yochai), where the hidden God "garbs" itself in these powers so as to be known, named, and related to. Scholem framed the Sefirot as the stages by which the concealed Ein Sof passes into the revealed God of religion, the personal Lord of prayer is, in effect, the Infinite clothed (Scholem, Major Trends, 1941; and Scholem's treatment of the Zohar). Moshe Idel, while challenging Scholem's emphases, agrees that the Sefirotic structure is the bridge between an unknowable absolute and an addressable deity (Idel, Kabbalah: New Perspectives, 1988). One careful flag: whether the Sefirot are God's very essence or merely God's instruments was itself a live Kabbalistic dispute, a tension Kabbalah preserved rather than resolved.
The tension with a personal God
Here is the genuine strain at the heart of the system. The God of Genesis and Exodus commands, relents, grows angry, loves. Ein Sof does none of these: it has no will, no name, no relation, because relation requires a second term and the Infinite admits no outside. So Kabbalah must hold two things at once: a personal, covenantal God and an impersonal abyss behind it. The Sefirot are the hinge. Idel argued that Kabbalists were not abandoning the biblical God but supplying a metaphysical depth-structure for him (Idel, Kabbalah: New Perspectives, 1988); Arthur Green similarly reads the Sefirotic God as the personal face of an impersonal ground (Green, A Guide to the Zohar, 2004). This is best held as a reconstruction of how the medieval Kabbalists resolved the strain, not as a settled doctrine, the texts themselves are layered and sometimes contradict one another.
This same architecture is why a power like Gevurah (divine severity, the fifth Sefirah) can be a facet of God rather than the whole: the Sefirot let Kabbalah distinguish God's faces without splitting God.
Apophatic theology: Kabbalah's negative path
Ein Sof places Kabbalah squarely inside the broad apophatic ("negative") current that runs through Jewish, Christian, and Islamic thought: the conviction that the highest reality is known best by saying what it is not. Within Judaism, Maimonides had already insisted (a century before the Zohar) that we can predicate of God only negations, never positive attributes (Maimonides, Guide for the Perplexed, c. 1190). Ein Sof radicalizes this into a name for the unnameable. The structural rhyme with other traditions is real but must be flagged honestly: the Christian "divine darkness" of Pseudo-Dionysius, the Eastern Christian distinction between God's unknowable essence and his energies, the Sufi al-Haqq beyond attributes. These are resonances you can lean on, not influence you can bank: convergent solutions to one problem (how can the finite speak the Infinite?), not a proven chain of borrowing. The essence/energies parallel is especially close in shape: an unknowable core, knowable expressions, but parallel structure is not transmission. Kabbalah's own most radical instrument in this current is the name Ayin, "Nothing": negation promoted from method to proper name.
Where caution is required
Two honest limits. First, Ein Sof is a medieval coinage; reading it back into the Bible or even into the Talmud is anachronism, however tempting. Second, Kabbalists disagreed sharply about its relation to the first Sefirah, Keter ("Crown"), some identified them, others insisted Keter is the first emanation out of an Ein Sof that remains forever beyond it. Scholem mapped these disputes precisely because they were never fully settled (Scholem, Major Trends, 1941; Origins of the Kabbalah, English trans. 1987). The lesson is methodological: Ein Sof is not one fixed doctrine but a site where Jewish mystics negotiated the oldest problem in theology. To present it as a tidy system is to flatten exactly what made it generative.
Common questions
What does Ein Sof mean?
The Hebrew Ein Sof literally negates: ein ("there is not") plus sof ("end" or "limit"), so it reads as "Without-End" or "the Infinite." It is a phrase that withholds rather than describes, closer to "the Limitless" than to a title. The very grammar is apophatic, a via negativa in two words.
Is Ein Sof in the Bible?
No. Ein Sof appears nowhere in the Hebrew Bible; it is a reconstructed theological category built to name what scripture leaves unnamed. It is a medieval coinage that entered Kabbalistic usage in the late twelfth and thirteenth centuries, so reading it back into the Bible or even into the Talmud is anachronism, however tempting.
What is the difference between Ein Sof and the Sefirot?
Ein Sof is God as utterly hidden, unsayable, prior to any self-disclosure. The Sefirot are the ten emanations (Keter, Hokhmah, Binah, Hesed, Gevurah, Tiferet, Netzah, Hod, Yesod, Malkhut) that flow out of the Infinite like light through a graded series of vessels, and they are how the concealed Ein Sof passes into the revealed, personal God of religion. Whether the Sefirot are God's very essence or merely God's instruments was itself a live Kabbalistic dispute, a tension Kabbalah preserved rather than resolved.
Is Ein Sof the same as the God of the Bible?
Not directly. The God of Genesis and Exodus commands, relents, grows angry, and loves, while Ein Sof has no will, no name, and no relation, because relation requires a second term and the Infinite admits no outside. The personal Lord of prayer is reached only through the Sefirot, the Infinite clothed; this is best held as a reconstruction of how the medieval Kabbalists resolved the strain, not as a settled doctrine.
This page maps Ein Sof as the apophatic limit of Kabbalah and the Sefirot as its bridge to a personal God; it does not settle the medieval disputes over essence-versus-instrument or Keter's identity, and it treats cross-tradition parallels as resonance, not lineage.
Sources
Gershom Scholem, Major Trends in Jewish Mysticism (1941) and Origins of the Kabbalah (English trans. 1987; German orig. Ursprung und Anfänge der Kabbala, 1962); Moshe Idel, Kabbalah: New Perspectives (1988); Arthur Green, A Guide to the Zohar (2004); the Zohar (late 13th c.); Maimonides, Guide for the Perplexed (c. 1190).