Psalm 51:1-4a, 10-12, 15

Have mercy on me O God in your great kindness:
in the fullness of your mercy blot out my offenses.
Wash away all my guilt: 
and cleanse me from my sin. For I acknowledge my faults:
 and my sin is always before me.
 Against you only have I sinned
and done evil in your sight. Create in me a clean heart O God:
 and renew a right spirit within me. 
Do not cast me away from your presence: 
do not take your holy spirit from me. Give me the joy of your help again:
 and strengthen me with a willing spirit.
 O Lord open my lips: 
and my mouth shall proclaim your praise.