3 “To the end, a Psalm to David himself.” No other end may thou look to, than is laid down for you by the Apostle himself. For “Christ is the end.”...He was of the seed of David, not after His Godhead, whereby He is the Creator of David, but after the flesh; therefore He deigned to be called David in prophecy: look to this “end,” for the Psalm is chanted “to David Himself;” hear the voice of His Body; be in His Body. Let the voice which you have heard be yours, and pray, and say what follows.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)