There are, in fact, three “Glorias.” There is the Gloria Tibi, used just before the reading of the Gospel in the Service of Holy Communion -- “Glory be to thee, O Lord.” Then there is the Gloria Patri, which is sung as a doxology after the reading of psalms --“Glory be to the Father, and to the Son and to the Holy Ghost.”
The third Gloria is the one with which we are concerned here, and it is this one which is generally meant when one speaks simply of “The Gloria.” It is the Gloria in excelsis, the great hymn of praise which, in our American Book of Common Prayer, concludes the Eucharistic Liturgy.
This ancient Greek hymn is drawn from various sources. It begins with the salutation used by the angels at our Savior’s birth. “Glory be to God on high, and on earth peace, good will towards men” (Luke 2:14). The hymn then continues to expand on this theme as it relates to God the Father.
In the second stanza, the Gloria turns its focus to God the Son, using phrases and themes very familiar to us from the Kyrie (“Lord, have mercy upon us.”) and the Agnus Dei (“O Lamb of God, that takest away the sins of the world.”)
The hymn concludes with a short third stanza which is renewed acclamation of praise for the Son as a part of the Holy Trinity.
The Eastern Church has used the Gloria in the Daily Offices since the fourth century. It was introduced into the mass itself in the Roman Church in the late fifth century. Cranmer did not disturb this use except that in the 1552 Book he moved it to the end of the service from its traditional position following the Kyrie, early in the Eucharist. Many Anglo-Catholic parishes in the Anglican Communion have reverted to this earlier placement.
Wherever it is placed, this “greater doxology” represents a mighty and joyous burst of praise and adoration. Penitence is intermixed with it, but taken a whole it is joyful. For this reason, it deserves the wholehearted participation of the worshipper, whether said or sung.
It is customary to omit the Gloria in the Anglican and Roman rites during the penitential seasons of Advent and Lent, substituting for it a verse or two of some appropriate hymn, often said rather than sung.