Psalm 51:4

I read Psalm 51 in the ESV last week, and I noticed a feature that's similar to what I found in Isaiah 1 a number of years ago.  Initially, every verse exhibits a sort of parallelism:

1 Have mercy on me, O God, according to your steadfast love;

according to your abundant mercy blot out my transgressions.

2 Wash me thoroughly from my iniquity,

and cleanse me from my sin!

3 For I know my transgressions,

and my sin is ever before me.

This structure is broken in the fourth verse, though:

4 Against you, you only, have I sinned and done what is evil in your sight, so that you may be justified in your words and blameless in your judgement.

There's no reiteration or doubling of the same sentiment here, and this more singular focus matches the exclusivity in the verse itself:  "against you, you only, have I sinned."