Jacob was born to Rabbi Yitzhak of
Slavuta,
Shepetivka,
Uman (
Polish–Lithuanian Commonwealth), and Be'er. During his formative years, he was recognized as a prodigy of rabbinic studies, and he studied with the
Maggid of Mezeritch and Rabbi
Pinchas of Koretz. Hasidic legend states that he was known for his erudition and teaching ability, causing him to be tasked by the Maggid with spreading Hasidic theology among rabbis in the area who disagreed with Hasidism. He eventually reached the Rabbi
Yechezkel Landau of
Prague, who was a well-renowned rabbi as far away as
Judea, who allegedly got into a fight with him about the importance of the book,
Toldot Yaakov Yosef, which Jacob won. The debate was recounted in Emery Noam by Rabbi Moshe Leib Shapira. Although originally making
Aliyah around 1790 through
Acre, he returned to Europe and later travelled back in 1795. He settled in the city of Tiberas, meeting
Abraham Kalisker. He travelled abroad in order to raise money for Polish immigrants living in Israel. He permanently returned in 1799, and settled in Haifa. In the book, '''', it is said that he bumped into the emissary of Rabbi
Nachman of Breslov, who was looking for a ship where Nachman could return home to. Jacob provided the money quickly to the emissary in fear that they would be caught by Ottoman authorities for trying to arrange funds for travel back to Europe. Nachman saw it as a sign that he should stay longer in the
Land of Israel. Later, Nachman reconciled with Abraham and Jacob. == Legacy ==