4 “For the enemy has persecuted my soul: he has humbled my life on the earth”. Here we speak, here our Head speaks for us. Manifestly both the devil persecuted the Soul of Christ and Judas the Soul of his Master: and now too the same devil remains to persecute the Body of Christ, and one Judas succeeds another. There lacks not then of whom the Body too may say, “For the enemy has persecuted my soul.” For what does each one who persecutes us endeavour save to make us abandon our heavenly hope, and savour of the earth, yield to our persecutor, and love earthly things?
“They have laid me in dark places, as the dead of the world.” This ye hear more readily from the Head; this ye perceive more readily in the Head. For He died indeed for us, yet was He not one of the “dead of the world.” For who are the “dead of the world”? And how was not He one of the “dead of the world”? “The dead of the world” are those who have died of their own desert, receiving the reward of iniquity, deriving death from the sin transmissed to them; according as it is said, “For I was conceived in iniquity.”...In dying, says He, I do the will of My Father, but I am not deserving of death.
Nought have I done wherefore I should die, yet is it My own doing that I die, that by the death of an innocent One, they may be freed who had wherefore they should die. “They set me in places,” as though in Hades, as though in the tomb, as though in His very Passion, “as the dead of the world.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)