(February 1965)
A revolutionary party and a revolutionary people must always undergo repeated education from both the positive and negative sides, and only through comparison and contrast can they be tempered and become mature, thereby securing the guarantee of victory. We Chinese Communists have positive teachers—namely, Marx, Engels, Lenin, and Stalin. We also have negative teachers—namely, Chiang Kai-shek, the Japanese imperialists, the U.S. imperialists, and those within our Party who committed the errors of "Left" or Right opportunist lines. If there were only positive teachers and no negative teachers, the Chinese revolution would not have been able to achieve victory. To belittle the role of negative teachers is not to be a thoroughgoing dialectical materialist.