Medieval Jewish philosophy contributed considerably to the mystical branch of Judaism known as Kabbalah. This movement is generally regarded as having its origins in twelfth and thirteenth-century Provence in the midrashically styled Bahir (Book of Enlightenment). Some, however, consider the much earlier Sefer Yetsirah (Book of Formation)—from the third through the seventh centuries—to be the earliest work of Kabbalah.

Chief among the philosophers who influenced concepts within Kabbalah were those who thrived in the Muslim cultures of Babylon (Iraq) and Spain. An example is Saadya Gaon (882—942), head of the Babylonian Yeshivah (religious academy) of Pumbedita. Although Saadya was a rationalist philosopher, he nevertheless published a detailed commentary on Sefer Yetsirah. In addition, he posited an intermediary between God and creation, known as the kavod or "glory." It is possible that this concept was influenced by the Karaite thinker, Benjamin al-Nahawandi (830–860), and that both were...