George Leo Haydock, on Ps 50:6

Only, or principally, who art the only God, (1 Timothy i. 17.; Worthington) the judge and witness of my crime. (Haydock) — David was a king, and acknowledged no judge among men. (St. Ambrose, c. x.) — Soli Deo reus est. (Cassiodorus) — Urias, whom he had injured, was no more. (St. Augustine) — The action had been done in secret: (2 Kings xii. 12.) but many began to suspect, and to blaspheme. (Haydock) — Judged. St. Paul reads thus, (Romans iii. 4.) though the Hebrew be, “when thou judgest.” St. Jerome has also judicaberis, so that we might infer, that the Hebrew is now incorrect, or that beshophtec means in judicare te. (Berthier) — Houbigant changes the order of the verses, “cleanse me from my sins, that thou mayst be blameless when thou comest into judgment: For I know,” &c. (Haydock) — Susanna was preserved from sinning by the thought of God’s presence, Daniel xiii. 25. — If David fell, he confessed his fault. (Berthier) — God is faithful to his promises, and desires the conversion of sinners, though some would represent him as cruel, and unconcerned about his creatures. The psalmist prevents this unjust inference, (Haydock) and proves, that God is both just and merciful. (Worthington) — He acknowledges his ingratitude, as the captives confess, that their sins have brought on them this chastisement, though they had not injured the Babylonians. (Theodoret) (Flaminius) (Calmet) — God had often promised pardon to those who truly repent. An appeal is made to his truth and mercy.