Karl Kautsky quotes
The worst reproach that Engels could make against the first English Marxists was that they were applying Marxism in a sectarian spirit. What would he have said, had he lived to see it, about a school of Marxists who after succeeding in capturing the state power proceeded to make a state religion of Marxism, a religion whose articles of faith and their interpretation are watched over by the government, a religion, the criticism of which, nay, the slightest deviation from which, is sternly punished by the State; a Marxism ruling by the methods of the Spanish Inquisition, propagated with fire and sword, practicing a theatrical ritual, as illustrated by the embalmed body of Lenin: a Marxism reduced to the status not only of a state religion but of a medieval or oriental faith? Such a Marxism may indeed be called a doctrinaire fanaticism.
Karl Kautsky