FROM CHAPTER 14:

Whence comes the impulse to proselytize? ... The missionary zeal seems rather an expression of some deep misgiving, some pressing feeling of insufficiency at the center. Proselytizing is more a passionate search for something not yet found than a desire to bestow upon the world something we already have. It is a search for a final and irrefutable demonstration that our absolute truth is indeed the one and only truth. The proselytizing fanatic strengthens his own faith by converting others. The creed whose legitimacy is most easily challenged is likely to develop the strongest proselytizing impulse. It is doubtful whether a movement which does not profess some preposterous and patently irrational dogma can be possessed of that zealous drive which "must either win men or destroy the world." It is also plausible that those movements with the greatest inner contradiction between profession and practice - that is to say with a strong feeling of guilt - are likely to be the most fervent in imposing their faith on others.

- Eric Hoffer, The True Believer; 1951; Harper Perennial