Yissachar Dov celebrated his bar mitzvah on 25 January 1961 (8 Shevat 5721) in the Tel Aviv beit medrash of Rebbe Aharon, where he sat by himself at the dais, greeting a few hundred guests. Back in yeshiva, he studied for many hours with private "chavrusas" (study partners), and prepared to receive rabbinic ordination. At the age of 15, he moved to an apartment which a group of Belzer Hasidim rented for him near the yeshiva, and began inviting other students to join him for Shabbat meals at which he delivered words of Torah and Hasidut.