The Zohar is an ancient, secret text of Kabbalah going back to a 2nd-century rabbi, Shimon bar Yochai, who received it directly from God

The Zohar ("Splendor" or "Radiance") is a sprawling, multi-volume body of mystical commentary on the Torah, written mostly in an artificial literary Aramaic and structured as teachings delivered by the 2nd-century Galilean sage Rabbi Shimon bar Yochai (often called "Rashbi") to his circle of disciples, traditionally said to have been composed while he hid from Roman persecution in a cave. Traditional Kabbalistic communities hold to that attribution. But the text itself entered history through one specific person: Moses de León, a Spanish Jewish mystic living in Guadalajara and later Ávila, who began circulating portions of the Zohar in the 1280s and presented them as ancient manuscripts he had recovered.

Modern academic scholarship, going back to the foundational work of historian Gershom Scholem in the 20th century (Major Trends in Jewish Mysticism) and refined since by scholars including Yehuda Liebes and Daniel Abrams, holds that Moses de León is the Zohar's actual primary author, writing in the late 13th century rather than transmitting a 2nd-century document. The evidence includes the Zohar's Aramaic, which linguists have identified as an artificial literary construction modeled on Aramaic found in the Talmud and Targums rather than the vernacular Aramaic an actual 2nd-century Galilean would have spoken; its citations and conceptual borrowings from medieval Jewish philosophy (including ideas that track with 12th- and 13th-century Provençal and Spanish Kabbalists such as the circle of Isaac the Blind); and testimony recorded after de León's death in 1305, when his widow reportedly told inquirers that her husband had written the work himself and attributed it to bar Yochai to give it greater authority and sale value.

Theologically, the Zohar describes a God, the Ein Sof ("the Infinite" or "without end"), who is fundamentally unknowable in his essence and becomes accessible to creation only through ten emanations called the sefirot, arranged in a structure commonly diagrammed as the "Tree of Life." These sefirot (names include Chokhmah/Wisdom, Binah/Understanding, Chesed/Mercy, and others) are presented as the channels through which the Infinite interacts with the finite world, and the Zohar builds an elaborate mystical psychology and cosmology around their interplay, including teachings on the transmigration of souls. This is a substantially different picture of God's nature and how he relates to creation than the plain narrative of Genesis or the rest of the Hebrew Bible offers, and it developed roughly 1,700 years after the Hebrew Bible's latest books were written, which is the core reason mainstream rabbinic Judaism through most of its history treated Kabbalah as an esoteric specialty for advanced scholars, not as required doctrine for the ordinary reader of the Torah.