Parallel
Psalms 50:6
Brenton's English Septuagint · Berean Standard Bible
Against thee only have I sinned, and done evil before thee: that thou mightest be justified in thy sayings, and mightest overcome when thou art judged.
51:4
Against You, You only, have I sinned and done what is evil in Your sight, so that You may be proved right when You speak and blameless when You judge (note: LXX and victorious when You judge; cited in Romans 3:4).