The Metaphysics of Morals by Immanuel Kant Chapter 1 Page 17

philanthropist, would he not still find in himself a source from whence to give himself a far higher worth than that of a good-natured temperament could be?

Unquestionably. It is just in this that the moral worth of the character is brought out which is incomparably the highest of all, namely, that he is beneficent, not from inclination, but from duty.

To secure one's own happiness is a duty, at least indirectly; for discontent with one's condition, under a pressure of many anxieties and amidst unsatisfied wants, might easily become a great temptation to transgression of duty. But here again, without looking to duty, all men have already the strongest and most intimate inclination to happiness, because it is just in this idea that all inclinations are combined in one total.