4 They who are such, neither do they account their righteousness as their own, but His, by the faith of whom they live (whence also the Apostle says, “That I may win Christ, and be found in Him, not having my own righteousness which is of the law, but that which is of the faith of Christ, the righteousness which is of God by faith;” and in another place, “That we may be the righteousness of God in Him.” Whence also he finds fault with the Jews in these words, “Being ignorant of God's righteousness, and wishing to establish their own righteousness, they have not submitted themselves to the righteousness of God”).
Whosoever then wish their good works to be so seen of men, that He may be glorified from whom they have received those things which are seen in them, and that thereby those very persons who see them, may through the dutifulness of faith be provoked to imitate the good, their light shines truly before men, because there beams forth from them the light of charity; theirs is no mere empty fume of pride; and in the very act they take precautions, that they do not their righteousness before men to be seen of them, in that they do not reckon that righteousness as their own, nor do they therefore do it that they may be seen; but that He may be made known, who is praised in them that are justified, that so He may bring to pass in him that praises that which is praised in others, that is, that He may make him that praises to be himself the object of praise.
Observe the Apostle too, how that when he had said, “Please all men in all things, as I also please all men in all things;” he did not stop there, as if he had placed in that, namely, the pleasing men, the end of his intention; for else he would have said falsely, “If I yet pleased men, I should not be the servant of Christ;” but he subjoined immediately why it was that he pleased men; “Not seeking,” says he, “my own profit, but the profit of many, that they may be saved.” So he at once did not please men for his own profit, lest he should not be “the servant of Christ;” and he did please men for their salvation's sake, that he might be a faithful Minister of Christ; because for him his own conscience in the sight of God was enough, and from him there shined forth in the sight of men something which they might imitate.
Source: Sermons on Selected Lessons of the New Testament (New Advent)