The most essential factor is persistence - the determination never to allow your energy or enthusiasm to be dampened by the discouragement that must inevitably come. James Whitcomb Riley
I must make MAGICK the essential factor in the life of ALL. Aleister Crowley
Thus proletarian violence has become an essential factor in Marxism. Let us add once more that, if properly conducted, it will have the result of suppressing parliamentary socialism, which will no longer be able to pose as the leader of the working classes and as the guardian of order. Georges Sorel