9 This then for the wicked that would hurt me: what for me? “But my soul shall rejoice in the Lord”; as in Him from whom it has heard, “I am your salvation;” as not seeking other riches from without; as not seeking to abound in pleasures and good things of earth; but loving freely the true Spouse, not from Him wishing to receive anything that may delight, but Him alone proposing to itself, by whom it may be delighted. For what better than God will be given unto me? God loves me: God loves you. See He has proposed to you, Ask what you will. If the emperor should say to you, Ask what you will, what commands, what dignities, would you burst forth with! What great things would you propose to yourself, both to receive and to bestow! When God says unto you, Ask what you will, what will you ask? Empty your mind, exert your avarice, stretch forward as far as possible, and enlarge your desire: it is not any one, but Almighty God that said, Ask what you will. If of possessions you are a lover, you will desire the whole earth, that all who are born may be your husbandmen, or your slaves. And what when you have possessed the whole earth? You will ask the sea, in which yet you can not live. In this greediness the fishes will have the better of you. But perhaps you will possess the islands. Pass over these also; ask the air although you can not fly; stretch your desire even unto the heavens, call your own the sun, the moon, and the stars, because He who made all said, Ask what you will: yet nothing will you find more precious, nothing will you find better, than Himself who made all things. Him seek, who made all things, and in Him and from Him shall you have all things which He made. All things are precious, because all are beautiful; but what more beautiful than He? Strong are they; but what stronger than He? And nothing would He give you rather than Himself. If anything better you have found, ask it. If you ask anything else, you will do wrong to Him, and harm to yourself, by preferring to Him that which He made, when He would give to you Himself who made....
“But my soul shall be joyful in the Lord; it shall rejoice in His salvation.” The salvation of God is Christ: “For my eyes have seen Your salvation.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)