If you ask me what is the distinguishing mark of the Communist, what it is that Communists most outstandingly have in common, . . . I would say that beyond any shadow of doubt it is their idealism, their zeal, dedication, devotion to their cause and willingness to sacrifice. 

The Communists' appeal to idealism (one of the keys to sacrifice) is direct and audacious. They say that if you make mean (British English for "meager"] little demands upon people, you will get a mean little response which is all you deserve, but, if you make big demands on them, you will get an heroic response.  They prove in practice that this is so, over and over again.  They work on the assumption that if you call for big sacrifices people will respond to this and, moreover, the relatively smaller sacrifices will come quite naturally. 

Like attracts like.  Those who are attracted by the dedication they see within the movement will themselves be possessed of a latent idealism, a capacity for dedication.  This dedication perpetuates itself.  It sets the tone and pace for the movement as a whole. This being so, the movement can make big demands upon its followers, knowing that the response will come. If the majority of members of an organization are half-hearted and largely inactive, it is not surprising of others who join it soon conform to the general pattern.  If the organization makes relatively few demands upon its members and if they quite obviously feel under no obligation to give a very great deal to it, then those who join may be forgiven for supposing that this is the norm and that this is what membership entails.

If, on the other hand, the majority of members, from the leaders down, are characterized by their single-minded devotion to the cause, if it is quite clear that the majority are giving until it hurts, putting their time, money, thought and if necessary life itself at its disposal, then those who consider joining will assume that this is what will be expected of them.  If they nonetheless make the decision to join, they will come already conditioned to sacrifice until it hurts.

The paradox . . . is that the Communists show a faith in their people, which Christians, who are supposed to be the great defenders of the human person, are too often not prepared to show.  They ask for a lot and they get the big response they expect.