| Honorific-Prefix: | Rabbi |
| Mordechai Jaffe | |
| Honorific-Suffix: | of Lechovitch |
| Birth Date: | 1742 |
| Death Date: | 18 January 1810 |
| Birth Place: | Nesvizh, Polish–Lithuanian Commonwealth |
| Death Place: | Stolin, Minsk Governorate, Russian Empire |
| Dynasty: | Lechovitch |
| Demonination: | Hasidism |
| Successor: | Rabbi Noach Yaffe |
| Father: | Noah HaPanchas |
Rabbi Mordechai Jaffe of Lechovitch (1742 – 18 January 1810) was a Hasidic rabbi who was the disciple of Rabbi Shlomo of Karlin and was the founder of the Lechovitch dynasty of Hasidism, from which the, Slonim, Koidanov, and Novominsk courts descended.[1] He was the president of the for Jews in Israel.
Jaffe was born in Nesvish in 1742 to Rabbi Noah HaPanchas of Nesvish, a descendant of Mordecai Yoffe, who raised him under the Jewish faith and officiated his Bar Mitzvah. For his education, he travelled to Rabbi Levi Yitzchak of Berditchev, who told Jaffe that "a third of the world rests on him".[2] He later studied under Rabbi Shlomo of Karlin.[3] He also travelled with his fellow student, Asher of Stolin (I), to Rabbi Boruch of Medzhybizh.[4]
After his marriage, Jaffe continued to live in Nesvizh until the death of Rabbi Shlomo in July 1792, who was killed by the Cossack army.[5] Following that development, he began to lead a community of Hasidism in Lyakhavichy, Belarus.[6] His followers numbered in the thousands, and as he grew more popular, he was arrested in 1799 by the Russian government due to opposition to his practices by Russian elite. He was arrested along with Rabbi Shneur Zalman of Liadi and Rabbi Asher of Stolin, and was released later in the year.[7]
He was appointed to serve as president of the Holy Land Fund on behalf of Kollel Raysin (of Belarus), where he worked extensively to financially support the Hasidic community in Eretz Yisrael, travelling to collect funds for them.[8]
Jaffe died in Stolin on 18 January 1810 (13 Shvat 5570), present in the city for the wedding of his grandson Rabbi Shlomo Chaim Perlov. His children surviving him were:
As the disciple of Rabbi Shlomo, Jaffe followed in the footsteps of Karlin Hasidism, which emphasizes the importance of prayer with enthusiasm. He also emphasized among his followers the need for simple faith by memorizing Maimonides' 13 Tenets of Faith. His commentary of the Torah was printed in many books, such as his grandson Rabbi Shalom of Breihin-Koidinov's "Divre Shalom", "Mishmeret Shalom", "Or Yasharim",[9] "Torat Avot",[10] and "Mira Dachia".[11]