St. Bernard of Clairvaux:
It is always natural for every rational being to desire what it sees to be finer and to direct its energies toward it. It is never satisfied with anything which lacks what it judges it should have. For example, a man who has a beautiful wife looks at lovelier women with a discontented eye or mind. He who is dressed in fine clothes wants better. He who is very rich envies a richer man. Today you see many men who already have great wealth and possessions still laboring day by day to add one field to another and to extend their boundaries with greed which knows no bounds. And you see those who have houses worthy of a king in vast palaces nevertheless adding house to house everyday, and building with a restless love of novelty, knocking down what they build, altering rectangles to rounds. And what of men in high positions? Do we not see them striving with all their might to reach still higher positions? Their ambition is never satisfied. There is no end to it all because the highest and the best is not to be found in any of these things. If a man cannot be at peace until he has the highest and best, is it surprising that he is not content with inferior and worse things? It is folly and extreme madness always to be longing for things which cannot only never satisfy, but cannot even blunt the appetite. However much you have of such things, you still desire what you have not yet attained. You are always restlessly sighing after what is missing. When the wandering mind is always rushing about in empty effort among the various and deceptive delights of the world, it grows weary and remains dissatisfied. It is like a starving man who thinks that whatever he is stuffing himself with is nothing in comparison with what remains to be eaten. He is always anxiously wanting what he has not got rather than enjoying what he has, for who could have everything? That little which a man obtains by all his efforts he possesses in fear. He does not know what he will lose and when. Thus the perverted will, which is aiming for the best and trying to make speed towards that which will fully satisfy it, fails in its endeavor. The wicked, therefore, walk around in a circle: naturally wanting what will satisfy their wants, and foolishly thrusting away their means of obtaining it—that is, obtaining not consumption but consummation.
– Quoted in Carl Trueman’s lecture, “Medieval Church 4: St. Bernard of Clairvaux.”
Only in God do the deepest longings of the human heart find their consummation: “The sorrows of those who run after another god shall multiply,” but “in your presence is fullness of joy; at your right hand are pleasures forevermore” (Ps 16:4, 11).