8 But that you may not commit iniquities, “beware of all covetousness.” I will tell you in its full extent, what is “of all covetousness.” In matter of lust he is covetous, whom his own wife suffices not. And idolatry itself is called covetousness; because again in matter of divine worship he is covetous, whom the one and true God suffices not. What but the covetous soul makes for itself many gods? What but the covetous soul makes to itself false martyrs? “Beware of all covetousness.”
Lo, you love your own goods, and dost boast yourself in that you seek not the goods of others; see what evil you do in not hearing Christ, who says, “Beware of all covetousness.” Love your own goods, do not take away the goods of others; you have the fruits of your labour, they are justly yours; you have been left an heir, someone whose good graces you have attained has given it to you; you have been on the sea, and in its perils, hast committed no fraud, hast sworn no lie, hast acquired what it has pleased God you should, and you are keeping it greedily as in a good conscience, because you do not possess it from evil sources, and dost not seek what is another's.
Yet if you give not heed to Him who has said, “Beware of all covetousness,” hear how great evils you will be ready to do for your own goods' sake. Lo, for example, it has chanced to you to be made a judge. You will not be corrupted, because you do not seek the goods of others; no one gives you a bribe and says, “Give judgment against my adversary.” This be far from you, a man, who seeks not the things of others, how could you be persuaded to do this? Yet see what evil you will be ready to do for your own goods' sake.
Peradventure he that wishes you to judge evilly, and pronounce sentence for him against his adversary is a powerful man, and able to bring up false accusation against you, that you may lose what you have. Thou dost reflect, and think upon his power, think of your own goods you are keeping, which you love: not which you have possessed, but in whose power rather you are yourself unhappily fixed. This your bird-lime, by reason of which you have not the wings of virtue free, you look to; and you say within your own self, “I am offending this man, he has much influence in the world; he will suggest evil accusations against me, and I shall be outlawed, and lose all I have.” Thus you will give unrighteous judgment, not when you seek another's, but when you keep your own.
Source: Sermons on Selected Lessons of the New Testament (New Advent)