For if, as we have often shown, this is a sure proof of being rich, to despise wealth, and to want nothing; and of poverty again, to want, and any one would more easily despise money in poverty than in wealth, it is quite evident that to be in poverty rather makes one to be rich. For indeed that the rich man sets his heart on money more than the poor man, is surely plain to every one; like as the drunken man is thirsty, rather than he that has partaken of drink sufficiently. For neither is his desire such as to be quenched by too much; but, on the contrary, it is its nature to be inflamed by this. For fire likewise, when it has received more food, then most of all waxes fierce; and the tyranny of wealth, when you have cast into it more gold, then most especially is increased.
If then the desiring more be a mark of poverty; and he that is in the possession of riches is like this; he is especially in poverty. Do you see that the soul then most of all is poor, when it is rich; and then is rich, when it is in poverty?
And if you will, let us exercise our reasoning in persons also, and let there be two, the one having ten thousand talents, the other ten, and from both let us take away these things. Who then will grieve the most? He that has lost the ten thousand. But he would not have grieved more, unless he had loved it more; but if he loves more, he desires more; but if he desires more, he is more in poverty. For this do we most desire, of which we are most in want, for desire is from want. For where there is satiety, there cannot be desire. For then are we most thirsty, when we have most need of drink.
And all these things have I said, to show that if we be vigilant, no one shall harm us; and that the harm arises not from poverty but from ourselves. Wherefore I beseech you with all diligence to put away the pest of covetousness, that we may both be wealthy here, and enjoy the good things eternal, unto which God grant we may all attain, by the grace and love towards man of our Lord Jesus Christ, to whom be glory world without end. Amen.
Source: Homilies on the Gospel of St. Matthew (New Advent)