The idea of duty, that recognition of something to be lived for beyond the mere satisfaction of self, is to the moral life what the addition of a great central ganglion is to animal life. No man can begin to mould himself on a faith or an idea without rising to a higher order of experience: a principle of subordination, of self-mastery, has been introduced into his nature; he is no longer a mere bundle of impressions, desires, and impulses.
The borrowing is often honest enough, and comes of magnanimity and stoutness. A great man quotes bravely and will not draw on his invention when his memory serves him with a word as good.