Aristotle, Nicomachean Ethics
H. Rackham, Ed.

Again, since activities differ in moral value, and some are to be adopted, others to be avoided, and others again are neutral, the same is true also of their pleasures: for each activity has a pleasure of its own. Thus the pleasure of a good activity is morally good, that of a bad one morally bad; for even desires for noble things are praised and desires for base things blamed; but the pleasures contained in our activities are more intimately connected with them than the appetites which prompt them, for the appetite is both separate in time and distinct in its nature from the activity, whereas the pleasure is closely linked to the activity, indeed so inseparable from it as to raise a doubt whether the activity is not the same thing as the pleasure.