Upon the death of his half-brother, Grand Rabbi Naftali Halberstam, Bobover chasidim crowned Rabbi Ben Zion as the Grand rabbi of Bobov, while a minority chose to follow Rabbi Mordecai David Unger a son-in-law of Grand Rabbi Naftali Halberstam.
Upon the death of his half-brother, Grand Rabbi Naftali Halberstam, Bobov split in two. Many chose to follow Rabbi Ben Zion, while many chose to follow Rabbi Mordecai David Unger a son-in-law of Grand Rabbi Naftali Halberstam.