(Sepher ha Zohar, ספר הזהר, "Book of Splendor" from Hebrew זֹהַר meaning splendor or radiance) A deeply important Hebrew scripture in the tradition of the Kabbalah.
"The Sepher ha Zohar ["Book of Splendor"] presumably was written by Simeon ben Jochai, a disciple of Akiba. Rabbi Simeon was sentenced to death about A.D. 161 by Lucius Verus, co-regent of the Emperor Marc Aurelius Antoninus. He escaped with his son and, hiding in a cave, transcribed the manuscript of the Zohar with the assistance of Elias, who appeared to them at intervals. Simeon was twelve years in the cave, during which time he evolved the complicated symbolism of the "Greater Face" and the "Lesser Face." While discoursing with disciples Rabbi Simeon expired, and the "Lamp of Israel" was extinguished. His death and burial were accompanied by many supernatural phenomena. The legend goes on to relate that the secret doctrines of Qabbalism had been in existence since the beginning of the world, but that Rabbi Simeon was the first man permitted to reduce them to writing. Twelve hundred years later the books which he had compiled were discovered and published for the benefit of humanity by Moses de León. The probability is that Moses de León himself compiled the Zohar about A.D. 1305, drawing his material from the unwritten secrets of earlier Jewish mystics." - Manly P. Hall, The Secret Teachings of All Ages (1928)
"Moses de Leon could not be the author or the forger of the Zoharic works in the XIIIth century, as he is accused of being, since Ibn Gebirol gave out the same philosophical teaching 225 years before the day of Moses de Leon. No true Kabalist or scholar will ever deny the fact. It is certain that Ibn Gebirol based his doctrines upon the oldest Kabalistic sources, namely, the "Chaldean Book of Numbers," as well as some no longer extant Midrashim, the same, no doubt, as those used by Moses de Leon. But it is just the difference between the two ways of treating the same esoteric subjects, which, while proving the enormous antiquity of the esoteric system, points to a decided ring of Talmudistic and even Christian sectarianism in the compilation and glossaries of the Zoharic system by Rabbi Moses. Ibn Gebirol never quoted from the Scriptures to enforce the teachings (vide I. Myer's Qabbalah, p. 7). Moses de Leon has made of the Zohar that which it has remained to this day, "a running commentary on the . . . Books of the Pentateuch" (ibid.), with a few later additions made by Christian hands." - H.P. Blavatsky, The Secret Doctrine (1888)