Aharon ben Jacob Perlov of Karlin (Hebrew: הגדול אהרן בן יעקב פרלוב מקרלין 1736 – 1772), known among the Ḥasidim as Rabbi Aharon the Great, or simply as the "Preacher" or "Censor", was one of the early rabbis of the sect who helped the rapid spread of Ḥasidism in Eastern Europe, and was distinguished for the fiery eloquence of his exhortations.
Perlov composed and wrote the famous Sabbath hymn Yah Ekhsof (יה_אכסוף) which is still a widely sung part of the liturgy of the Ḥasidim and has recently become popular among non-Hasidim as well.
[1] Perlov was born in Yanova to Yaakov of Kobrin, the brother of Rabbi Nachman of Kosov, and Perl.
During his teacher's lifetime, he established the Hasidic center in the city of Karlin (now a suburb of Pinsk in Belarus).
His gravestone in the Karlin cemetery reads: He merited and brought merit to many, many times, and devoted his life with mesirut nefesh for this, as his purpose was to bring merit to the many, and he rebuked the masses with open rebuke and hidden love to bring Israel closer to their Father in Heaven and unite them with true unity.His teachings were recorded by his disciples and primarily in the writings of his grandson, Rabbi Aharon of Karlin (the second), author of the book "Beit Aharon."