19 But what do you say, O Asaph, now in understanding? “Deliver not to the beasts a soul confessing to You”....To what beasts, save to those the heads whereof were broken in pieces upon the water? For the same devil is called, beast, lion, and dragon. Do not, he says, give to the Devil and his Angels a soul confessing to You. Let the serpent devour, if still I mind things earthly, if for things earthly I long, if still in the promises of the Old Testament, after the revealing of the New, I remain. But forasmuch as now I have laid down pride, and my own righteousness I will not acknowledge, but Your Grace; against me let proud beasts have no power. “The souls of Your poor forget Thou not unto the end.” Rich we were, strong we were: but You have dried up the rivers of Etham: no longer we establish our own righteousness, but we acknowledge Your Grace; poor we are, hearken to Your beggars. Now we do not dare to lift our eyes to Heaven, but smiting our breasts we say, “O Lord, be merciful to me a sinner.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)