A temporal thing that is obtained after being desired does not calm desire very much; the desire is always still there for something else. By contrast, spiritual reality extinguishes the desire for something else and removes desire itself. The reason is simple: as long as we do not possess something in this world, we regard it as fulfilling and of greater price. Once possessed, it no longer appears so precious… our desire is then enkindled once again. Spiritual reality, on the contrary, is known only when possessed… So that is why possessing it cheers the heart and provokes desire, not of course the desire for something else, but the desire that even an imperfect possession of the spiritual reality attains to.
Saint Thomas Aquinas