Moshe Mordechai's genius was detected from a very early age and he was called the illui from Bakst.

The child prodigy began studying in the Volozhin yeshiva at the age of 16, under the guidance of the legendary Torah giant Rabbi Chaim Soloveitchik.

In 1897, Nosson Tzvi Finkel, Slabodka's famed mashgiach ruchani), invited Epstein to become the rosh yeshiva.

Epstein accepted the post, while Meltzer moved together with some of his best talmidim to the town of Slutsk to lead the Ridvaz's yeshiva there.

The Slabodka yeshiva flourished under the joint leadership of Rabbis Epstein and Finkel, and many of its students were crucial in nurturing the spiritual level of the Jewish people in subsequent generations.

In late August 1929 mobs, incited by the antisemitic Mufti of Jerusalem, swarmed the yeshiva, killing over 67 Jews and wounding many more, in an event known as the 1929 Hebron massacre.