If you were going to compile a list of great books in religious Judaism, then Duties of the Heart, by Rabbi Bachya ben Joseph ibn Paquda (early eleventh century), would top the list. Luckily, Feldheim Publishers has a handsome two volume edition of this book in the Torah Classics Library series, so the book is available for all to read, either in Hebrew, or in English on the facing pace.
This book was originally written in Judeo-Arabic. It was translated by Yehuda ibn Tibbon, from the Tibbon family of Hebrew translators, shorty after it was written. To this day, the Hebrew version of Duties of the Heart is a widely read book among Chasidic Jews and followers of Mussar, the Jewish ethical movement. Duties focuses on the less explicitly stated Torah of the Heart, which includes an intellectual understanding of God’s oneness and indivisibility through a series of “Gates,” bringing the reader through to an understanding of God through an uncompromising monotheism.
This edition of Duties will not inform you that this book is heavily influenced by Sufi ideas. In fact, nearly every time Bachya mentions a “pious” person, and tells a story without citing the source, it from an oral Islamic tradition. In this sense, Duties represents a great fusion of Judaism with a kind of intellectual, ascetic, and morally driven Sufism.
Tibbon’s translation is also part of the wider scope of Jewish history. The Tibbon family translated numerous works from Judeo-Arabic into Hebrew. In the process, they were forced to coin new words, create new meanings, and push Hebrew into new arenas. In the process, they helped Hebrew become an international language. By doing this, they paved the way for the modern revival of a spoken, vernacular Hebrew. When people in the late nineteenth century wanted a model of how Hebrew could be grown, they could look at books like Duties as a model.
So reading Duties of the Heart is not only a fine exercise in creating a more perfect human being (and Jew), but also an important document at the crossroad of medieval and modern Jewish intellectual trends.