All the grand sources, in short, of human suffering are in a great degree, many of them almost entirely, conquerable by human care and effort; and though their removal is grievously slow—though a long succession of generations will perish in the breach before the conquest is completed, and this world becomes all that, if will and knowledge were not wanting, it might easily be made—yet every mind sufficiently intelligent and generous to bear a part, however small and unconspicuous, in the endeavour, will draw a noble enjoyment from the contest itself, which he would not for any bribe in the form of selfish indulgence consent to be without.
Source: wiktionary