“…the afternoon of April 19, [1943] two boys climbed up on the roof of the headquarters of the Jewish Resistance there and raised two flags: the red-and-white Polish flag and the blue-and-white banner of the ZZW (blue and white are the colors of the Flag of Israel today). These flags were well-seen from the Warsaw streets, and the Jews managed to hold off the Germans for four entire days in their attempts to remove them. Stroop recalled:
‘The matter of the flags was of great political and moral importance. It reminded hundreds of thousands of the Polish cause, it excited them and unified the population of the General Government, but especially Jews and Poles. Flags and national colors are a means of combat exactly like a rapid-fire weapon, like thousands of such weapons. We all knew that – Heinrich Himmler, Krüger, and Hahn. The Reichsfuehrer [Himmler] bellowed into the phone: ‘Stroop, you must at all costs bring down those two flags’.” – From an account of the Warsaw Ghetto Uprising that began on April 19, 1943