2 What this Psalm contains, I believe that you perceived when it was being chanted; for therein the Church of Christ, set in the midst of the wicked, complains and groans, and pours out prayer to God. For her voice is in every such prophecy the voice of one in need and want, not yet satisfied, “hungering and thirsting after righteousness,” for whom a certain fullness in the end has been promised, and is reserved....
Source: The Enarrations, or Expositions, on the Psalms (New Advent)