Career
He was one of the early great rabbis of the sect who helped the rapid spread of Ḥasidism in eastern Europe, and was distinguished for the fiery eloquence of his exhortations. Aaron is the author of the Sabbath hymn Yah Ekhsof which begins יה אכסוף נועם שבת and is still a part of the liturgy of the Ḥasidim.
