Did you not read our articles about the June revolution, and was not the essence of the June revolution the essence of our paper? Why then your hypocritical phrases, your attempt to find an impossible pretext? We have no compassion and we ask no compassion from you. When our turn comes, we shall not make excuses for the terror. But the royal terrorists, the terrorists by the grace of God and the law, are in practice brutal, disdainful, and mean, in theory cowardly, secretive, and deceitful, and in both respects disreputable.
--Karl Marx, in the final issue of Neue Rheinische Zeitung (18 May 1849) Marx-Engels Gesamt-Ausgabe, Vol. VI, p. 503
"Until its complete extermination or loss of national status, this racial trash always becomes the most fanatical bearer there is of counter-revolution, and it remains that. That is because its entire existence is nothing more than a protest against a great historical revolution... The next world war will cause not only reactionary classes and dynasties, but also entire reactionary peoples, to disappear from the earth. And that too is progress." -Karl Marx, 1849, Neue Rheinische Zeitung.
"The classes and the races too weak to master the new conditions of life must give way.... They must perish in the revolutionary holocaust." -Karl Marx (Marx People's Paper, April 16, 1856, Journal of the History of Idea, 1981)
“To the sentimental phrases about brotherhood which we are being offered here on behalf of the most counter-revolutionary nations of Europe, we reply that hatred of Russians was and still is the primary revolutionary passion among Germans; that since the revolution hatred of Czechs and Croats has been added, and that only by the most determined use of terror against these Slav peoples can we, jointly with the Poles and Magyars, safeguard the revolution. We know where the enemies of the revolution are concentrated, viz. in Russia and the Slav regions of Austria, and no fine phrases, no allusions to an undefined democratic future for these countries can deter us from treating our enemies as enemies. Slav nationality leaves the revolution entirely out of account, then we too know what we have to do” –Engles, Neue Rheinische Zeitung No. 223, February 16, 1849