5 “Be merciful unto me, O Lord, for I have cried unto You all day”. Not “one day:” understand “all day” to mean continually: from the time that the body of Christ groans being in afflictions, until the end of the world, when afflictions pass away, that man groans and calls upon God: and each one of us after his measure has his part in that cry in the whole body. You have cried in your days, and your days have passed away: another has come after you, and cried in his days: and thou here, he there, another elsewhere: the body of Christ cries all the day, its members departing and succeeding one another. One Man it is that reaches to the end of the world: the same members of Christ cry, and some members already rest in Him, some still cry, some when we shall be at rest will cry, and after them others will cry. It is the whole body of Christ whose voice He hears, saying, “Unto You have I cried all the day.” Our Head on the right hand of the Father intercedes for us: some members He recovers, others He scourges, others He cleanses, others He comforts, others He is creating, others calling, others recalling, others correcting, others restoring.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)