41 “Behold, I have coveted Your commandments: O quicken Thou me in Your righteousness”. Behold, I have coveted to love You with all my heart, and with all my soul, and with all my mind, and my neighbour as myself, but, “O quicken Thou me” not in my own, but “in Your righteousness,” that is, fill me with that love which I have longed for. Aid me that I may do that which Thou chargest me: Yourself give what Thou dost command. “O quicken Thou me in Your righteousness:” for in myself I had that which would cause my death: but I find not save in You whence I may live. Christ is Your righteousness, “Who of God is made unto us wisdom,” etc. And in Him I find Your commandments, which I have coveted, that in Your righteousness, that is, in Him, You may quicken me. For the Word Himself is God; and “the Word was made flesh,” that He Himself also might be my neighbour.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)