In the 1920s and 30s, a number of Jewish thinkers from outside the ḥasidic world—most prominently Martin Buber—began to mine ḥasidic teachings and practices as a source for spiritual renewal, seeking to make Judaism relevant, in their minds, in an increasingly secular era. Historians refer to their ideas as “neo-Ḥasidism.” Among the most influential of these in his own time was Hillel Zeitlin (1871-1942), who, unlike Buber, was himself raised in a ḥasidic family in Eastern Europe. Ariel Evan Mayse describes Zeitlin’s intellectual development:
Zeitlin enjoyed an energetic devotional life in his youth, a period that he later described as being filled with a rich, mystical intoxication with the divine presence. Yet in his adolescence Zeitlin became increasingly troubled by philosophy and higher criticism of the Bible, and his confrontation with modernity led Zeitlin away from the world of Ḥasidism. He immersed himself in the study of Western thought, publishing books on Spinoza and Nietzsche. . . . By the early 1900s, [however], he returned to [religion], and devoted his considerable literary talents to what he now saw as his life’s work: preserving the legacy of early Ḥasidism and rearticulating a vision of Jewish spirituality that was compelling to contemporary (and future) seekers.
Zeitlin is a neo-ḥasidic writer because he interpreted and combined a wide variety of early ḥasidic sources, and because he neither lived in a ḥasidic community nor committed himself to a particular ḥasidic [sect]. He sought to return to the spiritual vitality he believed lay at the root of Ḥasidism, but also felt compelled to reinterpret the sources of the ḥasidic tradition. His works, peppered with references to Western philosophy, were written in Hebrew and in Yiddish for secularized Polish Jews, hoping to provide them with a compelling spiritual alternative both to the balkanized, intensely political Jewish intellectual world of [non-ḥasidic] Warsaw and to the [insular ḥasidic world that very much persisted in Poland]. . . .
Zeitlin felt that it was his privilege and obligation, together with the rest of Polish Jewry, to ensure that the vital spiritual message of Ḥasidism did not founder. More than simply preserving and safeguarding Ḥasidism, Zeitlin saw his task as returning this movement of devotional renewal to its roots . . . so that it might develop anew and spread forth to include all peoples.
Read more on Lehrhaus: https://www.thelehrhaus.com/scholarship/the-development-of-neo-hasidism-echoes-and-repercussions-part-i-introduction-hillel-zeitlin-and-martin-buber/