8 Examine these contrary injunctions. “Keep for yourself,” says avarice. Suppose you are willing to obey her, ask her where you are to keep? Some well-defended place she will show you, walled chamber, or iron chest. Well, use all precautions; yet perhaps some thief in the house will burst open the secret places; and while you are taking precautions for your money, you will be in fear of your life. It may be while you are keeping up your store, he whose mind is set to plunder them, has it even in his thoughts to kill you. Lastly, even though by various precautions you should defend your treasure and your clothes against thieves; defend them still against the rust and moth. What can you do then? Here is no enemy without to take away your goods, but one within consuming them.
Source: Sermons on Selected Lessons of the New Testament (New Advent)