This setting is by the Italian Composer, Gregorio Allegri. It is based on Psalm 51 and was composed during the reign of Pope Urban VIII, probably in the 1630s.
Psalm 51, Miserere mei, Deus (Have mercy on me, O God) , is one of the penitential psalms used in the Ash Wednesday Proper Liturgy of the Episcopal Church.
1Have mercy on me, O God, according to your steadfast love; according to your abundant mercy blot out my transgressions.
2Wash me thoroughly from my iniquity, and cleanse me from my sin.
3For I know my transgressions, and my sin is ever before me.
4Against you, you alone, have I sinned, and done what is evil in your sight, so that you are justified in your sentence and blameless when you pass judgment.
5Indeed, I was born guilty, a sinner when my mother conceived me.
6You desire truth in the inward being; therefore teach me wisdom in my secret heart.
7Purge me with hyssop, and I shall be clean; wash me, and I shall be whiter than snow.
8Let me hear joy and gladness; let the bones that you have crushed rejoice.
9Hide your face from my sins, and blot out all my iniquities.
10Create in me a clean heart, O God, and put a new and right spirit within me.
11Do not cast me away from your presence, and do not take your holy spirit from me.
12Restore to me the joy of your salvation, and sustain in me a willing spirit.
13Then I will teach transgressors your ways, and sinners will return to you.
14Deliver me from bloodshed, O God, O God of my salvation, and my tongue will sing aloud of your deliverance.
15O Lord, open my lips, and my mouth will declare your praise.
16For you have no delight in sacrifice; if I were to give a burnt offering, you would not be pleased.
17The sacrifice acceptable to God is a broken spirit; a broken and contrite heart, O God, you will not despise.
18Do good to Zion in your good pleasure; rebuild the walls of Jerusalem,
19then you will delight in right sacrifices, in burnt offerings and whole burnt offerings; then bulls will be offered on your altar.