Career
At that time, he was the rabbi of the city of Shargorod for several years, and he was expelled from his position on a Friday afternoon in 1748. In several of his responsa, which he wrote in Rashkov, where he took up residence after his banishment from Sharogrod, he reveals the suffering which he had undergone. His book, Toldos Yaacov Yosef, (published on 1780), was the first chassidic work ever published.
In it repeats the phrase, "I have heard from my teacher", 249 times.
He is one of the foremost sources for teachings from the Baal Shem Tov.