6 “Lay not up for yourselves treasures on earth, where moth and rust does destroy, and where thieves break through and steal: But lay up for yourselves treasures in heaven, where no thief approaches, nor moth corrupts: For where your treasure is, there will your heart be also.” What more do you wait for? The thing is plain. The counsel is open, but evil desire lies hid; nay, not so, but what is worse, it too lies open. For plunder does not cease its ravages; avarice does not cease to defraud; maliciousness does not cease to swear falsely.
And all for what? That treasure may be heaped together. To be laid up where? In the earth, and rightly indeed, by earth for earth. For to the man who sinned and who pledged us, as I have said, our cup of toil, was it said, “Earth you are, and to earth shall you return.” With good reason is the treasure in earth, because the heart is there. Where then is that, “we lift them up unto the Lord?” Sorrow for your case, you who have understood me; and if you sorrow truly, amend yourselves. How long will you be applauding and not doing? What you have heard is true, nothing truer. Let that then which is true be done. One God we praise, yet we change not, that we may not in this very praise be disquieted in vain.
Source: Sermons on Selected Lessons of the New Testament (New Advent)