Before invading Poland, Germany signed the Nazi-Soviet Nonaggression Pact, securing the eastern border of Germany. Limited trade, mostly on the part of the Russians, was part of the agreement. But everyone involved knew that it was a measure on both sides to buy time. Ideologically, both nations despised the other. Hitler had devoted much of Mein Kampf to his believe in the menace of Communism. Nazism was against everything Communism stood for.
Part of the operational planning of the German high command involved a possible invasion of the Soviet Union. On July 21, a month after the fall of France, Hitler summoned Generalfeldmarshal Walther von Brauchitsch and instructed him to plan for an invasion of the Soviet Union