1 It may be attributed to David himself, not the Mediator, the Man Christ Jesus, but the whole Church now perfectly established in Christ.
2. “Judge me, O Lord, for I have walked in my innocence”. Judge me, O Lord, for, after the mercy which You first showed me, I have some desert of my innocence, the way whereof I have kept. “And trusting in the Lord I shall not be moved.” And yet not even so trusting in myself, but in the Lord, I shall abide in Him.
3. “Prove me, O Lord, and try me”. Lest, however, any of my secret sins should be hid from me, prove me, O Lord, and try me, making me known, not to You from whom nothing is hid, but to myself, and to men. “Burn my reins and my heart.” Apply a remedial purgation, as it were fire, to my pleasures and thoughts. “For Your mercy is before my eyes”. For, that I be not consumed by that fire, not my merits, but Your mercy, whereby You have brought me on to such a life, is before my eyes. “And I have been pleasing in Your truth.” And since my own falsehood has been displeasing to me, but Your truth pleasing, I have myself been pleasing also with it and in it.
4. “I have not sat with the council of vanity”. I have not chosen to give my heart to them who endeavour to provide, what is impossible, how they may be blessed in the enjoyment of things transitory. “And I will not enter in with them that work wickedly.” And since this is the very cause of all wickedness, therefore I will not have my conscience hid, with them that work wickedly.
5. “I have hated the congregation of evil doers.” But to arrive at this council of vanity, congregations of evil doers are formed, which I have hated. “And I will not sit with the ungodly”. And, therefore, with such a council, with the ungodly, I will not sit, that is, I will not place my consent. “And I will not sit with the ungodly.”
6. “I will wash mine hands amid the innocent”. I will make clean my works among the innocent: among the innocent will I wash mine hands, with which I shall embrace Your glorious gifts. “And I will compass Your altar, O Lord.”
7. “That I may hear the voice of Your praise.” That I may learn how to praise You. “And that I may declare all Your wondrous works”. And after I have learned, I may set forth all Your wondrous works.
8. “O Lord, I have loved the beauty of Your house:” of Your Church. “And the place of the habitation of Your glory”: where You dwell, and art glorified.
9. “Destroy not my soul with the ungodly”. Destroy not then, together with them that hate You, my soul, which has loved the beauty of Your house. “And my life with the men of blood.” And with them that hate their neighbour. For Your house is beautified with the two commandments.
10. “In whose hands is wickedness.” Destroy me not then with the ungodly and the men of blood, whose works are wicked. “Their right hand is full of gifts”. And that which was given them to obtain eternal salvation, they have converted into the receiving this world's gifts, “supposing that godliness is a trade.”
11. “But I have walked in mine innocence: deliver me, and have mercy on me”. Let so great a price of my Lord's Blood avail for my complete deliverance: and in the dangers of this life let not Your mercy leave me.
12. “My foot has stood in uprightness.” My Love has not withdrawn from Your righteousness. “In the Churches I will bless You, O Lord”. I will not hide Your blessing, O Lord, from those whom You have called; for next to the love of You I join the love of my neighbour.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)