Polish hatred against Germans can be seen throughout history. It didn't just happen after World War 1 and during World War 2.
"Poki swiat swiatem, Polak Niemcowi nie bedzie bratem." is a Polish proverb, and translated into English it means:
"As long as the world will exist, the Pole will never be the German's brother."
Another Polish proverb: "Zdechly Niemiec, zedechly pies, mala to roznica jest."
"A croaked German, is a croaked dog, is just a small difference."
Here is the text of a Polish-Catholic war song which was sung in 1848 at the Pan-Slavic Congress in Prague:
"Brothers, take up your scythes! Let us hurry to war! Poland's oppression is over, we shall tarry no more. Gather hordes about yourselves. Our enemy, the German, shall fall! Loot and rob and burn! Let the enemies die a painful death. He that hands the German dogs will gain God's reward. I, the provost, promise you shall attain Heaven for it. Every sin will be forgiven, even well-planned murder, if it promotes Polish freedom everywhere. But cruses on the evil one who dares speak well of Germany to us. Russia and Prussia must fall. Hail the Polish banner! So rejoice ye all: Polzka zyje, great and small!"
Not only did these so called "Christian" priests excel in rhetoric aimed at cultivating deadly hate against Germans during the pre-1939 years, they also prayed in their churches, "O wielk wojn ludow prosimy Cie, Panie! (We pray to you for the great War of Peoples, oh Lord!)" Later, when their wishes came true, they actively participated in murdering unsuspecting German soldiers. "Cardinal Wyszynski confirmed the fact 'that during the war there was not one single Polish priest who did not fight against the Germans with a weapon in his hand.' The war lasted only three short weeks, the German occupation lasted several years. This explains the extraordinary high number of priest-partisans who even were joined by bishops." Immediately after the formation of Poland after World War 1, Poland was attacking Germans and Ukrainians. On August 26th, 1920, the Polish pastor in Adelnau said in a speech, "All Germans residing in Poland ought to be hanged." (1)