R. Menahem Nahum b. Zvi Twersky of Chernobyl (1730–1787), was educated in Lithuanian yeshivot. After his marriage he eked out a living as a teacher. Influenced by the kabbalistic teachings of R. Isaac Luria, he practiced self-mortification, and with the spread of Hasidism he journeyed to Medzhibozh to visit R. Israel b. Eliezer Ba'al Shem Tov. After the latter's death R. Menahem became one of the prominent disciples of R. Dov Baer of Mezhirech, and was one of the first to propagate Hasidism; he was then accepted as Maggid (preacher) at Chernobyl, where he lived in penury. The Mitnaggedim were extremely hostile toward him and sometimes insulted him while he was preaching. Among the principles he stressed in particular was the purification of man's moral attributes: "so long as his moral attributes are not purified [a man] will not be worthy of the Torah (Me'or Einayim, Lekh Lekha); every day of the week should be devoted to the purification of one particular attribute; the first day to love; the second to fear of G-d; etc." (ibid., Be-Shallah).