4 Then, because he had said, “He who will save shall lose it, but whosoever shall lose shall save it,” and on that side had set salvation and destruction, and on this salvation and destruction; to prevent any one's imagining the one destruction and salvation to be all the same with the other, and to teach you plainly that the difference between this salvation and that is as great as between destruction and salvation; from the contraries also He makes an inference once for all to establish these points. “For what is a man profited,” says He, “if he gain the whole world, and lose his own soul?”
Do you see how the wrongful preservation of it is destruction, and worse than all destruction, as being even past remedy, from the want of anything more to redeem it? For “tell me not this,” says He, “that he that has escaped such dangers has saved his life; but together with his life put also the whole world, yet what profit has he thereby, if the soul perish?”
For tell me, should you see your servants in luxury, and yourself in extreme calamity, will you indeed profit anything by being master? By no means. Make this reckoning then with regard to your soul also, when the flesh is in luxury and wealth, and she awaiting the destruction to come.
“What shall a man give in exchange for his soul?”
Again, He dwells upon the same point. What? Have you another soul to give for this soul? Says He. Why, should you lose money, you will be able to give money; or be it house, or slaves, or any other kind of possession, but for your soul, if you lose it, you will have no other soul to give: yea, though you had the world, though you were king of the whole earth, you would not be able, by paying down all earthly goods, with the earth itself, to redeem but one soul.
And what marvel, if it be so with the soul? Since even in the body one may see that so it turns out. Though thou wear ten thousand diadems, but have a body sickly by nature, and incurable, you will not be able, not by giving all your kingdom, to recover this body, not though thou add innumerable persons, and cities, and goods.
Now thus I bid you reason with regard to your soul also; or rather even much more with regard to the soul; and do thou, forsaking all besides, spend all your care upon it. Do not then while taking thought about the things of others, neglect yourself and your own things; which now all men do, resembling them that work in the mines. For neither do these receive any profit from this labor, nor from the wealth; but rather great harm, both because they incur fruitless peril, and incur it for other men, reaping no benefit from such their toils and deaths. These even now are objects of imitation to many, who are digging up wealth for others; or rather we are more wretched even than this, inasmuch as hell itself awaits us after these our labors. For they indeed are staid from those toils by death, but to us death proves a beginning of innumerable evils.
But if you say, you have in your wealth the fruit of your toils: show me your soul gladdened, and then I am persuaded. For of all things in us the soul is chief. And if the body be fattened, while she is pining away, this prosperity is nothing to you (even as when the handmaiden is glad, the happiness of the maidservant is nothing to her mistress perishing, nor is the fair robe anything compared with the weak flesh); but Christ will say unto you again, “What shall a man give in exchange for his soul?” on every hand commanding you to be busied about that, and to take account of it only.
Source: Homilies on the Gospel of St. Matthew (New Advent)