Sefer Yetzirah

Sefer Yetzirah, or the Book of Formation, is one of the earliest and most mysterious Jewish mystical texts. It describes the creation of the universe through Hebrew letters, numbers, and the “ten sefirot,” though its system is earlier and different from later medieval Kabbalah.

The text became very important for Jewish mysticism, cosmology, and later Kabbalistic thought. Even though its exact date and authorship are debated, it is one of the key bridges between ancient Jewish mystical ideas and the later development of Kabbalah.