Summary: David bookends calling for God's judgement on his enemies with calling for God's judgement on himself.
Response: I'm not sure I could be so bold. I know I'm guilty of quite a bit. Maybe if it were one of a bunch of passing judgements instead of a singular, permanent one?
I had a thought for a metaphor last night at our Ash Wednesday service: which is cleaner, the cup that sits in the China cabinet or the cup that gets used and washed every day? Obviously the former starts out cleaner but, unless you come and dust it often and well, it gets dirty over time, requiring cleaning that is more difficult because of how fragile it is. Holiness is not a one time thing and trying to keep it that way. It gets neglected that way, and is less useful. Holiness, to me, is a daily surrender and cleansing, in the hopes that less and less will need rinsed off each day.