Introduction Sefer Yeirah is one of the most enigmatic, yet influential, texts in the history of Jewish thought. The text is striking for its rhythmic phrasing and evocative language; it connects the essence of language with the foundations of the world. This short treatise has fascinated Jewish thinkers and kabbalists, as well as Western thinkers and writers, from Gottfried Wilhelm Leibniz to Umberto Eco and Jorge Luis Borges. Because of its unique style as well as the fact that it does not explicitly refer to other Jewish sources and was not quoted by other Jewish sources in late antiquity, it is difficult, if not impossible, to contextualize. When I present Sefer Yeirah for the first time to my students, I joke that after about 150 years of scholarship on Sefer Yeirah , we know almost everything about this book except for four minor issues: Who wrote it? Where and when was it written? What does it mean? And what was its "original" version? Scholars disagree about the time and context of the book, proposing first-century ce Hellenism, the rabbinic sphere of the second to sixth centuries CE, Neoplatonism of the fourth or fifth centuries CE, fifth to the sixth century CE Palestine, the Syriac-Christian milieu of the sixth to seventh century, or the ninth-century Islamic world. This diversity reflects what seems to be an inherent and radical inability to contextualize Sefer Yeirah . Sefer Yeirah appeared in the Jewish world at the beginning of the tenth century. In this period, it was already interpreted as a canonical treatise by leading rabbinic figures living on three continents, and it had many different versions.

The surprising appearance of Sefer Yeirah , as if out of the blue, is the result of its absence from the Jewish world before the tenth century, along with its immediate acceptance. Furthermore, Sefer Yeirah had a remarkable reception in Jewish milieus from the tenth century on. Joseph Dan describes the two main stages of its impact on the Jewish world--stages with little in common: in the first, between the tenth and the twelfth centuries, it was read by at least five commentators as a sort of philosophical or scientific text. In the second, from the end of the twelfth century on, it was interpreted by mystics and kabbalists as a mystical, mythical, and magical treatise. These facts about Sefer Yeirah ''s reception raise essential questions: Where was Sefer Yeirah before its canonization in the tenth-century rabbinic world? Why was Sefer Yeirah initially understood as a philosophical and scientific treatise, and later viewed as the canonical composition of Jewish mysticism? My main goal in this book is to demonstrate that the evolution of Sefer Yeirah and its reception have something in common: they point us to an alternative picture of the history of Jewish thought in late antiquity and the early Middle Ages. I claim that Sefer Yeirah is a rare surviving Jewish treatise written and edited around the seventh century by Jews who were familiar with Syriac Christianity and were far from the main circles of rabbinic learning. Sefer Yeirah does not show strong awareness of the articulations, insights, or even the existence of the rabbinic world. Sefer Yeirah , to put it slightly differently, conveys much information about its intellectual world in terms of language, physiology, astrology, and cosmology.

We have no reason to assume that the text tries to conceal its context; it is more reasonable to assume that our information about its world is limited. Sefer Yeirah is a unique, fascinating, and information-packed trace of another and unknown Jewish environment. Similarly, in the second part of the book, when we follow the mystical, magical, or mythical ways in which Sefer Yeirah was understood before the end of the twelfth century, a trace of another Jewish milieu beyond the scope of the medieval canon of familiar rabbinic figures comes into view. An investigative integration of the above hypotheses can help us outline the "margins of Jewish mysticism," a Jewish mystical thought that was not included in the classical canon of Jewish thought, for various historical reasons, but that was very important for the development of a Jewish horizon of thought. My conclusions, as with any scholarly work, are based on the work of other scholars, and references to their works are to be found throughout the book. I want to mention the works of four authors who particularly helped me reach my conclusions. Shlomo Pines''s paper on the similarities between the first chapter of Sefer Yeirah and the Pseudo-Clementine homilies brings important evidence to bear in support of the possibility of a Christian-Syriac context for Sefer Yeirah . Guy Stroumsa, in his article about a possible Zoroastrian origin to the perception of the sefirot in Sefer Yeirah , referred to the importance of the sixth-century treatise The Mysteries of the Greek Letters , which, as I will demonstrate, can be of much help in contextualizing Sefer Yeirah .

Haggai Ben-Shammai''s article on the reception of Sefer Yeirah claims convincingly that Saadya''s aims in interpreting Sefer Yeirah were apologetic and probably a reaction to other Sefer Yeirah commentaries concerned with myth, mysticism, and magic. And in two articles, Klaus Herrmann discusses fragments of commentaries to Sefer Yeirah preserved in the Cairo Geniza, written between the end of the tenth century or the beginning of the eleventh, in the spirit of Hekhalot literature. These fragments clearly demonstrate that there were other Jewish approaches to Sefer Yeirah before the end of the twelfth century, of which we know very little today. My work begins where these important studies leave off. Sefer Yeirah : A Short Introduction Sefer Yeirah opens with the following depiction of the creation of the world, from what it calls "thirty-two wondrous paths of wisdom":[With] thirty-two wondrous paths of wisdom, YH, the Lord of hosts, the God of Israel, the Living God, God Almighty, high and exalted, dwelling forever, and holy is his name (Isa. 57:15), created his universe with three books ( sefarim ): with a book (s.p/f.r) and a book (s.

p/f.r) and a book (s.p/f.r). Ten sefirot belimah and twenty-two foundation letters. Ten sefirot belimah , the number of ten fingers, five opposite five, and the covenant of unity is exactly in the middle, by the word of tongue and mouth and the circumcision of the flesh. Ten sefirot belimah , ten and not nine, ten and not eleven. Understand with wisdom, and be wise with understanding.

Test them and investigate them. Know and ponder and form. Get the thing clearly worked out and restore the Creator to his place. And their measure is ten, for they have no limit. Ten sefirot belimah , restrain your heart from thinking and restrain your mouth from speaking, and if your heart races, return to where you began, and remember that thus it is written: And the living creatures ran to and fro (Ezek. 1:14) and concerning this matter the covenant was made.Accordingly, the number thirty-two, constituting the paths of wisdom, comprises the twenty-two letters of the Hebrew alphabet--the foundation letters--and the "ten sefirot belimah ." The meaning of belimah is unclear, and I think that the most reasonable meaning of the word sefirot is, as Yehuda Liebes suggests, "counting" ( ); therefore, the phrase refers to the decimal counting system.

In the paragraphs that we have just quoted, the ten sefirot are joined to the twenty-two letters of the Hebrew alphabet to constitute a new numerical formula of thirty-two, which it calls the "thirty-two wondrous paths of wisdom." Scrutinizing these passages, which discuss the role of the ten sefirot , it seems at first glance that Sefer Yeirah demands precision. The numbers are not to be read differently: "Ten sefirot belimah , ten and not nine, ten and not eleven." It would seem that the numbers, in their precision, specify some kind of scientific or magical quality. Because of the numbers'' ontological and epistemological qualities, a reader of Sefer Yeirah is obliged to understand their role in the creation of the world and in the created world: "Understand with wisdom, and be wise with understanding. Test them and investigate them. Know and ponder and form. Get the thing clearly worked out.

" Along with its enthusiastic pathos about the obligation to investigate the world with numbers and letters, Sefer Yeirah warns readers about the very thing it counsels thinking!: "Ten sefirot belimah , restrain your heart from thinking and restrain your mouth from speaking, and if your heart races, return to where you began." Regarding this gap between the obligation to investigate and the restriction on inquiry, Liebes has noted that it should be understood not only as a contradiction but also as an essential part of the dialectical path charted by Sefer Yeirah . According to Liebes, Sefer Yeirah is not merely a cosmogonic treatise; it would more accurate to read it as a treatise about heavenly creativity and the human creativity inspired by the creation of the world. He says that Sefer Yeirah is actually a treatise of ars poetica that argues creativity''s need of both terms: one should understand the world and articulate one''s insights, while also making room for asto.