3 And let the rich give ear, if indeed they are rich; let them give ear to the Apostle, “Charge the rich of this world,” for there are who are the rich of another world. The poor are the rich of another world. The Apostles are the rich of another world, who said, “As having nothing, and yet possessing all things.” So that you may know of what poor he is speaking he added, “of this world.” Let the “rich” then “of this world” give ear to the Apostle, “Charge,” he says, “the rich of this world, that they be not proud in their conceits.” The first worm of riches is pride. A consuming moth, which gnaws the whole, and reduces it even to dust. “Charge them,” therefore, “not to be proud in their conceits, nor to trust in the uncertainty of riches” (they are the Apostle's words), “but in the living God.” A thief may take away your gold; who can take away your God? What has the rich man, if he has not God? What has the poor man not, if he have God? Therefore he says, “Nor to trust in riches, but in the living God, who gives us all things richly to enjoy;” with which all things He gives also Himself.
Source: Sermons on Selected Lessons of the New Testament (New Advent)