20 “Hear my prayer, O Lord”. Whereof shall I rejoice? Whereof should I groan? I rejoice on account of what is past, I groan longing for these which are not yet come. “Hear my prayer, and give ear unto my cry. Hold not Your peace at my tears.” For do I now no longer weep, because I have already “passed by,” have “left behind” so great things as these? “Do I not weep much the more?” For, “He that increases knowledge, increases sorrow.” The more I long for what is not here, do I not so much the more groan for it until it comes? Do I not so much the more weep until it comes?...
Source: The Enarrations, or Expositions, on the Psalms (New Advent)