Introduction:

The liturgy of the word begins with Trisagion (Greek "thrice holy") "Holy God, holy mighty One, holy immortal One, have mercy on us. It is sung three times with three different incipits. The hymn originated in the Antiochene (West Syriac) tradition. It was first performed in 451 AD as the Council of Chalcedon (Pathikulangara 1998: 170-171). Because of its theological appeal other Eastern churches adopted the hymn into their liturgies. In the Latin rite, the hymn is sung during the Good Friday service. As in the case of the opening hymn, the Trisagion is sung here three times in three ascending pitch registers (Eb, F, & G). The liturgy prescribes the following performance practice: the deacon invites the faithful to raise their voices and praise the living God; the choir and the congregation sing the hymn; the celebrant, deacon, and the servers together repeat the hymn with the prefix “Glory be to the Father and to the Son, and to the Holy Spirit;” and finally, the choir and the congregation sing the hymn with the prefix “for ever and ever, amen.”