3 My Mercy and my Refuge, my Upholder and my Deliverer. Much toils this combatant, having his flesh lusting against his spirit. Keep what you have. Then shall you have in full what you wish, when “death shall have been swallowed up in victory;” when this mortal body has been raised, and is changed into the condition of the angels, and rises aloft to a heavenly quality....There is life, there are good days, where nought lusts against the spirit, where it is not said, “Fight,” but “Rejoice.”
But who is he that lusts for these days? Every man certainly says, “I do.” Hear what follows. I see that you are toiling, I see that you are engaged in battle, and in danger; hear what follows:...“Depart from evil, and do good:” let not the poor first weep under you, that the poor may rejoice through you. For what reward, since now you are fighting? “Seek peace, and ensue it.” Learn and say, “My Mercy and my Refuge, mine Upholder and my Deliverer, my Protector:” “mine Upholder,” lest I fall; “my Deliverer,” lest I stick; “my Protector,” lest I be stricken. In all these things, in all my toil, in all my battles, in all my difficulties, in Him have I hoped, “who subdues my people under me.” Behold, our Head speaks together with us.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)