Jewish forms of esotericism existed over 2,000 years ago. Ben Sira warns against it, saying: "You shall have no business with secret things".[3] Nonetheless, mystical studies were undertaken and resulted in mystical literature. The first to appear within Judaism was the Apocalyptic literature of the second and first pre-Christian centuries and which contained elements that carried over to later Kabbalah. According to Josephus, such writings were in the possession of the Essenes and were jealously guarded by them against disclosure, for which they claimed a certain antiquity (see Philo, De Vita Contemplativa, iii., and Hippolytus, Refutation of all Heresies, ix. 27).
That books containing secret lore were kept hidden away by (or for) the "enlightened" is stated in 2 Esdras xiv. 45–46, where Pseudo-Ezra is told to publish the twenty-four books of the canon openly that the worthy and the unworthy may alike read, but to keep the seventy other books hidden in order to "deliver them only to such as be wise" (compare Dan. xii. 10); for in them are the spring of understanding, the fountain of wisdom, and the stream of knowledge.
Instructive for the study of the development of Jewish mysticism is the Book of Jubilees written around the time of John Hyrcanus. It refers to mysterious writings of Jared, Cain, and Noah, and presents Abraham as the renewer, and Levi as the permanent guardian, of these ancient writings. It offers a cosmogony based upon the twenty-two letters of the Hebrew alphabet, connected with Jewish chronology and Messianology, while at the same time insisting upon the heptad (7) as the holy number, rather than upon the decadic (10) system adopted by the later haggadists and observable in the Sefer Yetzirah. The Pythagorean idea of the creative powers of numbers and letters was shared with Sefer Yetzirah and was known in the time of the Mishnah before 200 CE.
Early elements of Jewish mysticism can be found in the non-Biblical texts of the Dead Sea Scrolls, such as the Songs of the Sabbath Sacrifice. Some parts of the Talmud and the Midrash also focus on the esoteric and mystical, particularly Hagigah 12b-14b. Many esoteric texts, among them Hekalot Rabbati, Sefer HaKana, Sefer P'liyah, Midrash Otiyot d'Rabbi Akiva, the Bahir, and the Zohar, claim to be from the Tannaitic era (10-220 CE), but all of these works, with the exception of Hekhalot, were actually composed 800-1,000 years later.
Kabbalists attribute Sefer Yetzirah to the patriarch Abraham, though the text itself offers no claim as to authorship and modern scholars consider it medieval.