Rabbi Ziemba also took an active role in the Agudas Yisroel at an early stage. At its first "Knessia Gedola" (great gathering), he was not yet forty when chosen to serve as honorary secretary in the Moetzes Gedolei HaTorah. At the second "Knessia Gedola", Rabbi Chaim Ozer Grodzenski agreed to serve as chairman of the Moetzes Gedolei HaTorah only if Rabbi Ziemba would continue in his position, while the forty-five-year-old Rabbi Ziemba felt himself to be too young and sought to stay in the background. At the third "Knessiah Gedolah" in 1937 in Marienbad, Austria, which played witness to the last massive gathering of European Orthodoxy before the Holocaust, Rabbi Ziemba was at the height of his fame. He spoke twice to the full assemblage and each time was greeted with hushed silence and awe.