Ps 58:17

“"My Helper, to Thee I will play, because Thou, O God, art my taker up" (ver. 17). What was I, unless Thou didst succour? How much despaired of was I, unless Thou didst heal? Where was I lying, unless Thou didst come to me? Certes with a huge wound I was endangered, but that wound of mine did call for an Almighty Physician. To an Almighty Physician nothing is incurable. ...Lastly, thinking of all good things whatsoever we may have, either in nature or in purpose, or in conversion itself, in faith, in hope, in charity, in good morals, in justice, in fear of God; all these to be only by His gifts, he hath thus concluded: "My God is my mercy:" He being filled with the good things of God hath not found what he might call his God, save "his mercy." O name, under which no one must despair! If thou say, my salvation, I perceive that He giveth salvation; if thou say, my refuge, I perceive that thou takest refuge in Him; if thou say, my strength, I perceive that He giveth to thee strength: "my mercy," is what? All that I am is of Thy mercy. ...”

“What tongue, then, can sufficiently narrate the depths of divine mercy? What spirit does not stand amazed at the riches of such great kindness? The Psalmist considered these riches of divine kindness when he said: "My helper, to you I will sing praise, for you, O God, are my protector, my God, my mercy." Behold, perceiving in what labors human life is placed, he called God his helper; and because he receives us from present tribulation into eternal rest, he also calls him protector. But considering that he looks upon and bears our evils, tolerates our faults, and yet reserves us through penitence for rewards, he did not wish to call God merciful, but called him mercy itself, saying: "My God, my mercy." Let us therefore recall before our eyes the evils we have done, let us weigh with how great benignity of God we are tolerated, let us consider what are the depths of his kindness, so that he not only pardons faults but also promises the heavenly kingdom to the penitent even after their faults. And from all the depths of our heart let us say individually, let us all say: "My God, my mercy."”