12 Shall we then say, that in addition to this health of body men may desire for themselves and for those dear to them honour and power? By all means, if they desire these in order that by obtaining them they may promote the interest of those who may be their dependants. If they seek these things not for the sake of the things themselves, but for some good thing which may through this means be accomplished, the wish is a proper one; but if it be merely for the empty gratification of pride, and arrogance, and for a superfluous and pernicious triumph of vanity, the wish is improper. Wherefore, men do nothing wrong in desiring for themselves and for their kindred the competent portion of necessary things, of which the apostle speaks when he says: “Godliness with a competency [contentment] is great gain; for we brought nothing into this world, and it is certain we can carry nothing out: and having food and raiment, let us be therewith content. But they that will be rich fall into temptation, and a snare, and into many foolish and hurtful lusts, which drown men in destruction and perdition; for the love of money is the root of all evil, which while some coveted after, they have erred from the faith, and pierced themselves through with many sorrows.” This competent portion he desires without impropriety who desires it and nothing beyond it; for if his desires go beyond it, he is not desiring it, and therefore his desire is improper. This was desired, and was prayed for by him who said: “Give me neither poverty nor riches: feed me with food convenient for me: lest I be full, and deny You, and say, Who is the Lord? Or lest I be poor, and steal, and take the name of my God in vain.” You see assuredly that this competency is desired not for its own sake, but to secure the health of the body, and such provision of house and clothing as is befitting the man's circumstances, that he may appear as he ought to do among those among whom he has to live, so as to retain their respect and discharge the duties of his position.
13. Among all these things, our own welfare and the benefits which friendship bids us ask for others are things to be desired on their own account; but a competency of the necessaries of life is usually sought, if it be sought in the proper way, not on its own account, but for the sake of the two higher benefits. Welfare consists in the possession of life itself, and health and soundness of mind and body. The claims of friendship, moreover, are not to be confined within too narrow range, for it embraces all to whom love and kindly affection are due, although the heart goes out to some of these more freely, to others more cautiously; yea, it even extends to our enemies, for whom also we are commanded to pray. There is accordingly no one in the whole human family to whom kindly affection is not due by reason of the bond of a common humanity, although it may not be due on the ground of reciprocal love;
Source: Letters (New Advent)