sentences:  After Rav Simcha Bunim's death, Rav Mordechai Yosef joined the court of his long-time childhood friend, Rabbi Menachem Mendel of Kotzk.The Kotzker Rebbe appointed him to guide the young chassidim who joined the ranks in Kotzk.When the Kotzker Rebbe began distancing himself from his chassidim, Rav Mordechai Yosef felt it was time for him to begin leading those who were in need of a Rebbe.