In January 1943, in a meeting of the Warsaw Jewish leadership, Rabbi Ziemba proclaimed that traditional martyrdom (Kiddush HaShem-Sanctification of the Divine Name) was no longer an option as a response to Nazi persecution. He stated that "sanctification of the Divine Name" must be done through resistance to the enemy. He said to a group of ghetto leaders, “In the present we are faced by an arch foe, whose unparalleled ruthlessness and total annihilation purposes know no bounds. Halachah law demands that we fight and resist to the very end with unequaled determination and valor for the sake of Sanctification of the Divine Name.”With the outbreak of World War II and the German invasion of Poland, Rabbi Ziemba became the single most important force in the Warsaw Ghetto. In the darkest days of despair, he was a source of hope, optimism and inspiration. He set up secret locations for the study of Torah, and at great personal risk, constantly visited these clandestine places to strengthen those who studied there. His wife died in the ghetto.