4 And as these things are said of the future, though the sound of the words is past, it follows: “Turn us, O God of our salvation”. That which he had just related as if it were done, how prays he that it may be done, except because he wished to show that he had spoken as if of the past in prophecy? But that it was not yet done which he had said was done he shows by this, that he prays that it may be done: “Turn us, O God of our salvation, and turn away Your anger from us.” Did you not say before: “You have appeased all Your anger, You have turned Yourself from Your wrathful indignation”? How then now do you say, “And turn away Your anger from us”? The Prophet answers: These things I speak of as done, because I see them about to be done: but because they are not yet done, I pray that they may come, which I have already seen.
5. “Be not angry with us for ever”. For by the anger of God we are subject to death, and by the anger of God we eat bread on this earth in want, and in the sweat of our face. This was Adam's sentence when he sinned: and that Adam was every one of us, for “in Adam all die;” the sentence passed on him has taken effect after him on us. For we were not yet ourselves, but we were in Adam: therefore whatever happened to Adam himself took effect on us also, so that we should die: for we all were in him....So far as this the sin of your father hurts you not, if you have changed yourself, even as it would not hurt your father if he had changed himself. But that which our stock has received unto its subjection to death, it has derived from Adam. What has it so derived? That frailty of the flesh, this torture of pains, this house of poverty, this chain of death, and snares of temptations; all these things we carry about in this flesh; and this is the anger of God, because it is the vengeance of God. But because it was so to be, that we should be regenerated, and by believing should be made new, and all that mortality was to be removed in our resurrection, and the whole man was to be restored in newness; “For as in Adam all die, so also in Christ shall all be made alive;” seeing this the Prophet says, “Be not angry with us for ever, nor stretch out Your wrath from one generation to another.” The first generation was mortal by Your wrath: the second generation shall be immortal by Your mercy....
6. “O God, You shall turn us again, and make us alive”. Not as if we ourselves of our own accord, without Your mercy, turn unto You, and then You shall make us alive: but so that not only our being made alive is from You, but our very conversion, that we may be made alive. “And Your people shall rejoice in You.” To their own evil they shall rejoice in themselves: to their own good they shall rejoice in You. For when they wished to have joy of themselves, they found in themselves woe: but now because God is all our joy, he that will rejoice securely, let him rejoice in Him who cannot perish. For why, my brethren, will you rejoice in silver? Either your silver perishes, or thou: and no one knows which first: yet this is certain, that both shall perish; which first, is uncertain. For neither can man remain here always, nor can silver remain here always: so too gold, so garments, so houses, so money, so broad lands, so, lastly, this light itself. Be not thou willing then to rejoice in these: but rejoice in that light which has no setting: rejoice in that dawn which no yesterday precedes, which no tomorrow follows. What light is that? “I,” says He, “am the Light of the world.” He who says unto you, “I am the Light of the world,” calls you to Himself. When He calls you, He converts you: when He converts you, He heals you: when He has healed you, you shall see your Converter, unto whom it is said, “Show us Your mercy, O Lord, and grant us Your salvation”: Your salvation, that is, Your Christ. Happy is he unto whom God shows His mercy. He it is who cannot indulge in pride, unto whom God shows His mercy. For by showing him His salvation He persuades him that whatever good man has, he has not but from Him who is all our good. And when a man has seen that whatever good he has he has not from himself, but from his God; he sees that everything which is praised in him is of the mercy of God, not of his own deserving; and seeing this, he is not proud; not being proud, he is not lifted up; not lifting himself up, he falls not; not falling, he stands; standing, he clings fast; clinging fast, he abides; abiding, he enjoys, and rejoices in the Lord his God. He who made him shall be unto him a delight: and his delight no one spoils, no one interrupts, no one takes away....Therefore, what says John in his Epistle? “Beloved, now are we the sons of God, and it does not yet appear what we shall be.” Who would not rejoice, if suddenly while he was wandering abroad, ignorant of his descent, suffering want, and in a state of misery and toil, it were announced, You are the son of a senator: your father enjoys an ample patrimony on your family estate; I bid you return to your father: how would he rejoice, if this were said to him by some one whose promise he could trust? One whom we can trust, an Apostle of Christ, has come and said to us, You have a father, you have a country, you have an inheritance. Who is that father? “Beloved, we are the sons of God.”...Therefore He promised us to show Himself unto us. Think, my brethren, what His beauty is. All those beautiful things which you see, which you love, He made. If these are beautiful, what is He Himself? If these are great, how great is He? Therefore from these things which we love here, let us the more long for Him: and despising these things, let us love Him: that by that very love we may by faith purify our hearts, and His vision, when it comes, may find our heart purified. The light which shall be shown unto us ought to find us whole: this is the work of faith now. This is what we have spoken here: “And grant us Your salvation:” grant us Your Christ, that we may know Your Christ, see Your Christ; not as the Jews saw Him and crucified Him, but as the Angels see Him, and rejoice.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)