Many people also resisted the Nazis in a non-violent way, sometimes termed "Spiritual Resistance". Anything that broke a Nazi law was a form of resistance as it gave meaning to their lives. Jews created synagogues, underground theatres, newspapers, schools, Youth Movements, soup kitchens - and more.

Rav Nussenbaum, in the Ghetto, wrote of the principle of "Kiddush Hechaim" (The Sanctification of Life). He wrote that, whereas in previous times, there was a principle of "Kiddush Hashem" (The Sanctification of G-d), whereby people chose to die, rather then transgress certain laws or morals - in the world of the Ghetto, there was a new imperative: the situation demanded Jews struggle to live, to prove that the Nazis would not be able to destroy them. Thus trying both to ensure basic needs, like food smuggling and observing Jewish laws where possible, were ways of sanctifying life and, as such, an imperative.

Our sources of information about this period are numerous, particularly survivors who have told their story. One major source is Oneg Shabbat, a group of intellectuals, historians, writers and others in the Ghetto who researched, collected and documented everything they could about the Ghetto so that people like us would know about it. Despite the dreadful conditions, they wrote with incredible objectivity. The leader was Dr. Emanuel Ringelblum, a historian and a member of Poalei Zion. As the liquidation drew near, the archives were hidden in three milk churns under the Ghetto. Almost all the writers were killed, including Ringelblum, but after the War, two of the three milk churns were recovered; the third has never been found. They are an incredible source of information about life and activity in the Ghetto and have helped historians enormously.

There were of course, a number of other sources, including private diaries, Nazi and Polish documents.