Chassidic leader.

Rabbi Yitzchak Isaac was the son of Rabbi Yisachar Barish, who was the brother of the famous tzaddik Rabbi Tzvi Hirsh of Zidichov (1763-1831). Rabbi Yitzchak Isaac was a very close disciple of Rabbi Tzvi Hirsh of Zidichov until the latter passed away from the world. He later studied under famous chassidic leader Rabbi Shalom of Belz.

Rabbi Yitzchak Isaac of Ziditchov once remarked that for 54 years consecutively he never slept through midnight (except during an emergency), but always arose and said the prayer of tikkun chatzot. This meant that he must have begun this practice when he was approximately fourteen years old.

Rabbi Yitzchak Isaac was known for his powerful prayers, that did not go unanswered. 

May the merit of the tzaddik Rabbi Yitzchak Isaac of Zidichov, protect us all, Amen.