What it is the man's interest to do or refrain from depends less on any outward circumstances than upon what sort of man he is.
 John Stuart Mill, Considerations on Representative Government (1861). copy citation

Context

“When we talk of the interest of a body of men, or even of an individual man, as a principle determining their actions, the question what would be considered their interest by an unprejudiced observer is one of the least important parts of the whole matter. As Coleridge observes, the man makes the motive, not the motive the man. What it is the man's interest to do or refrain from depends less on any outward circumstances than upon what sort of man he is. If you wish to know what is practically a man's interest, you must know the cast of his habitual feelings and thoughts. Every body has two kinds of interests—interests which he cares for and interests which he does not care for.” source