Have mercy on me, O God,
according to Your loving devotion;
according to Your great compassion,
blot out my transgressions.
Wash me clean of my iniquity
and cleanse me from my sin.
For I know my transgressions,
and my sin is always before me.
Against Thee, against Thee 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.

Surely I was brought forth in iniquity;
I was sinful when my mother conceived me.
Surely You desire truth in the inmost being;
You teach me wisdom in the inmost place.
Purify me with hyssop, and I will be clean;
wash me, and I will be whiter than snow.

Let me hear joy and gladness;
let the bones You have crushed rejoice.
Hide Your face from my sins
and blot out all my iniquities.
Create in me a clean heart, O God,
and renew a right spirit within me.
Cast me not away from Your presence;
take not Your Holy Spirit from me.
Restore to me the joy of Your salvation,
and sustain me with a willing spirit.

–Psalm 51:1-12