K. Liebknecht: Message of Greetings by the Spartakusbund to the Founding Congress of the Communist Workers Party of Poland (1918)

Only the social revolution of the German proletariat can extend the socialist upheaval of the working class which has begun in Russia into the world revolution of the international proletariat. Only the world revolution can and will secure an enduring and well-founded peace in the interests of all peoples. Only this can and will root out national antagonisms and replace nationalist hate by the closest solidarity of the peoples. Only this can free the working masses of all countries from the prison house of political oppression, social deprivation and economic exploitation…

Counterrevolution or social revolution —that is the iron alternative that imposes itself today on the German proletariat. It will pursue its struggle with greater zeal and much more rapidly achieve success the more it receives support and encouragement through the revolutionary struggle of its class comrades in other countries.

In your congress, in your decision to unite your ranks in order to increase your forces, to raise the readiness of the Polish proletariat to struggle, the revolutionary German proletariat sees a new signal of expanding world storm —the social revolution which alone can unite and revive the Polish nation on the ground of socialism.

All our wishes go to you.

Long live the social revolution of the Polish proletariat!
Long live the social revolution of the German proletariat!
Long live the Russian Soviet Republic!
Long live the world revolution of the international proletariat!

Karl Liebknecht, December 1918.