De Decalogo

But what is it that I am saying? The appearance and idea of a present good, or of one that is accounted such, rouses up and excites the soul which was previously in a state of tranquillity, and raises it to a high degree of elation, like a light suddenly flashing before the eyes; and this passion of the soul is called pleasure.

But the contrary to good is evil, which, when it forces its way in, and inflicts a mortal wound, immediately fills the soul against its will with depression and despondency; and the name of the passion is sorrow.