3 “But play ye to His name”. What has he said? By you “playing” let His name be blessed. But what it is to “play”? To play is also to take up an instrument which is called a psaltery, and by the striking and action of the hands to accompany voices. If therefore ye jubilate so that God may hear; play also something that men may both see and hear: but not to your own name....For if for the sake of yourselves being glorified ye do good works, we make the same reply as He made to certain of such men, “Verily I say unto you, they have received their reward:” and again, “Otherwise no reward ye will have with your Father that is in Heaven.” You will say, ought I, then, to hide my works, that I do them not before men?
No. But what says He? “Let your works shine before men.” In doubt then I shall remain. On one side You say to me, “Take heed that you do not your righteousness before men:” on the other side You say to me, “Let your good works shine before men;” what shall I keep? What do? What leave undone? A man can as well serve two masters commanding different things as one commanding different things. I command not, says the Lord, different things. The end observe, for the end sing: with what end you do it, see thou.
If for this reason you do it, that you may be glorified, I have forbidden it: but if for this reason, that God may be glorified, I have commanded it. Play therefore, not to your own name, but to the name of the Lord your God. Play ye, let Him be lauded: live ye well, let Him be glorified. For whence have ye that same living well? If for everlasting ye had had it, you would never have lived ill; if from yourselves ye had had it, you never would have done otherwise than have lived well.
“Give glory to His praise.” Our whole attention upon the praise of God he directs, nothing for us he leaves whence we should be praised. Let us glory thence the more, and rejoice: to Him let us cleave, in Him let us be praised. You heard when the Apostle was being read, “See ye your calling, brethren, how not many wise after the flesh, not many mighty, not many noble, but the foolish things of the world God has chosen to confound the wise.”...But the Lord chose afterwards orators also; but they would have been proud, if He had not first chosen fishermen; He chose rich men; but they would have said that on account of their riches they had been chosen, unless at first He had chosen poor men: He chose Emperors afterwards; but better is it, that when an Emperor has come to Rome, he should lay aside his crown, and weep at the monument of a fisherman, than that a fisherman should weep at the monument of an Emperor.
“For the weak things of the world God has chosen to confound the strong,” etc....And what follows? The Apostle has concluded, “That there might not glory before God any flesh.” See ye how from us He has taken away, that He might give glory: has taken away ours, that He might give His own; has taken away empty, that He might give full; has taken away insecure, that He might give solid....
Source: The Enarrations, or Expositions, on the Psalms (New Advent)