"We consider that the Cuban Revolution contributed three fundamental lessons to the conduct of revolutionary movements in America. They are: (1) Popular forces can win a war against the army. (2) It is not necessary to wait until all conditions for making revolution exist; the insurrection can create them. (3) In underdeveloped America the countryside is the basic area for armed fighting."
January 1, 1970
https://en.wikiquote.org/wiki/Che_Guevara