The man who acts solely from a regard to what is right and fit to be done, from a regard to what is the proper object of esteem and approbation, though these sentiments should never be bestowed upon him, acts from the most sublime and godlike motive which human nature is even capable of conceiving.
 Adam Smith, The Theory of Moral Sentiments (1759). copy citation

Context

“As even in the love of virtue, therefore, there is still some reference, though not to what is, yet to what in reason and propriety ought to be, the opinion of others, there is even in this respect some affinity between it, and the love of true glory. There is, however, at the same time, a very great difference between them. The man who acts solely from a regard to what is right and fit to be done, from a regard to what is the proper object of esteem and approbation, though these sentiments should never be bestowed upon him, acts from the most sublime and godlike motive which human nature is even capable of conceiving. The man, on the other hand, who while he desires to merit approbation is at the same time anxious to obtain it, though he too is laudable in the main, yet his motives have a greater mixture of human infirmity.” source