Finally, they labour everywhere for the union and agreement of the democratic parties of all countries.
The Communists disdain to conceal their views and aims. They openly declare that their ends can be attained only by the forcible overthrow of all existing social conditions. Let the ruling classes tremble at a Communistic revolution. The proletarians have nothing to lose but their chains. They have a world to win.
Working Men of All Countries, Unite! Page 34- Communist Manifesto

“Undoubtedly,” it will be said, “religious, moral, philosophical, and juridical ideas have been modified in the course of historical development. But religion, morality, philosophy, political science, and law, constantly survived this change.”

“There are, besides, eternal truths, such as Freedom, Justice, etc., that are common to all states of society. But Communism abolishes eternal truths, it abolishes all religion, and all morality, instead of constituting them on a new basis; it therefore acts in contradiction to all past historical experience.” Page 26 Communist Manifesto