13 Listen, then, with all your power, to the commendation of Grace, whereby you are saved without price. “For Your Name's sake, O Lord, You shall quicken me in Your righteousness”; not in my own: not because I have deserved, but because You have mercy. For were I to show my own desert, nought should I deserve of You, save punishment. You have pruned off from me my own merits; You have grafted in Your own gifts. “You shall bring forth my soul out of tribulation.” “And in your mercy shall bring mine enemies to destruction: and you shall destroy all them that afflict my soul; for I am Your servant”.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)