11 “For the Lord has heard the voice of my weeping; The Lord has heard my supplication; the Lord has received my prayer”. The frequent repetition of the same sentiments shows not, so to say, the necessities of the narrator, but the warm feeling of his joy. For they that rejoice are wont so to speak, as that it is not enough for them to declare once for all the object of their joy. This is the fruit of that groaning in which there is labour, and those tears with which the couch is washed, and bed drenched: for, “he that sows in tears, shall reap in joy:” and, “blessed are they that mourn, for they shall be comforted.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)