The Holy Shelah's great work influenced Hasidism.
Reprinted from The Jewish Religion: A Companion, published by Oxford University Press.
Isaiah Horowitz was a Polish rabbi, kabbalist, and author (1570-1630). Horowitz was born in Prague but studied in Poland under distinguished Talmudists. After serving as rabbi in Frankfurt-on-Main, Horowitz returned to Prague in 1614 to become rabbi there. In 1621 he journeyed to Palestine where he became rabbi of Jerusalem. Horowitz died in Tiberias where he was buried near to the tomb of Maimonides.
Horowitz's major work is his Sheney Luhot Ha-Berit, or The Two Tablets of Stone, published in Amsterdam in 1649. The title of this book was abbreviated, after its initial letters, to Shelah and Horowitz himself is usually referred as "the Holy Shelah." The work, encyclopedic in range, consists of biblical commentaries, kabbalistic discourses, explanations of the precepts and rituals of Judaism, ethical teachings, liturgical notes, and a treatment of Talmudic methodology. The work had a great influence on Jewish pietists, especially
in Hasidism. As an example of Horowitz's stance can be quoted his analysis of the Talmudic concept derekh eretz ('good conduct'). Horowitz writes, in the section of his work arranged in alphabetical order:
"The meaning of Derekh Eretz is correct behavior, extraordinary humility, improvement of the character, and all delightful things, to love all creatures and to be loved by them, to be a man of peace and a perfect man, contributing to the world in general and in particular in both spiritual and worldly matters. Derekh Eretz is conducted in three ways: 1) the way of perfect conduct by a man for himself; 2) the way of perfect conduct for a man in his home; 3) the way of perfect conduct by a man in relation to his fellows."