Latin:
Agnus Dei, qui tollis peccata mundi, miserere nobis.
Agnus Dei, qui tollis peccata mundi, miserere nobis.
Agnus Dei, qui tollis peccata mundi, dona nobis pacem.

English:
Lamb of God, who takes away the sins of the world, have mercy upon us.
Lamb of God, who takes away the sins of the world, have mercy upon us.
Lamb of God, who takes away the sins of the world, grant us peace.

Scripture References:
st. = John 1:29, Matt. 20:30

The Agnus Dei is an ancient church text that developed from John the Baptist's salutation of Christ: "Look, the Lamb of God, who takes away the sin of the world!" (John 1 :29; Isa. 53:7; Rev. 5:6-14). By the late seventh century this Latin text was introduced into the Roman Catholic Mass at a point just prior to the reception of communion. In the tenth century the Agnus Dei's third clause was changed to its present wording, "dona nobis pacem" ("grant us peace").

The translation of the text into German included the uniquely Lutheran addition of "Christe" to the beginning of each clause. This translation was first published in Low German in 1528 in Johannes Bugenhagen's manual Der Erbarn Stadt Brunswig Christlike Ordeninge. The English version in the Psalter Hymnal is an adaptation of the Lutheran text mixed with a translation provided by the International Committee on English in the Liturgy, a Roman Catholic group that has been active ever since Vatican II (1962-¬65). In any language the text is a profound but short prayer for mercy and peace.

Liturgical Use:
Lord's Supper; Lent, though traditionally used in any season; service of confession and forgiveness.

--Psalter Hymnal Handbook