A Prayer for Cleansing and Pardon from David once the prophet Nathan approached him after he committed adultery with Bathsheba.

Psalms 51

1 Have mercy on me, O God, according to your merciful 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.
4 Against you, you only, have I sinned, and done that which is evil in your sight,
so that you are justified in your sentence and blameless in your judgment.
....
10 Create in me a clean heart, O God, and put a new and right spirit within me.
11 Cast me not away from your presence, and take not your holy Spirit from me.
12 Restore to me the joy of your salvation, and uphold me with a willing spirit.
13 Then I will teach transgressors your ways, and sinners will return to you.
.....
17 The sacrifice acceptable to God is a broken spirit; a broken and contrite heart, O God, you will not de