Since returning to Kharkiv, Ukraine in May, Rabbi Moshe Moskovitz has done his best to ensure the continuity of Jewish life in the shell-battered city. But when a community member, Masha, asked him to plan a b’rit milah for her soon-to-be-born son, the challenges of war time came home for Rabbi Moskovitz. Just a few short months ago, arranging a brit was an everyday occurrence. Now, there wasn’t a mohel left in the country. Rabbi Moskovitz reached out to his colleagues, and Rabbi Mendel Cohen, the Chabad emissary to war-ravaged Mariupol who currently resides in Israel, answered the call. But...