The Gloria is based on the hymn of the angels in the Gospel of Luke (2:14):
_"Glory to God in the highest, and on earth peace among those whom he favors!"_
The traditional text of the Gloria in English is as follows:
_"Glory to God in the highest, and on earth peace to people of good will. We praise you, we bless you, we adore you, we glorify you, we give you thanks for your great glory, Lord God, heavenly King, O God, almighty Father. Lord Jesus Christ, Only Begotten Son, Lord God, Lamb of God, Son of the Father, you take away the sins of the world, have mercy on us; you take away the sins of the world, receive our prayer; you are seated at the right hand of the Father, have mercy on us. For you alone are holy, you alone are the Lord, you alone are the Most High, Jesus Christ, with the Holy Spirit, in the glory of God the Father. Amen._
The Gloria is typically sung or chanted during the Eucharistic liturgy, at the beginning of the Mass or Divine Liturgy. It is also used in other liturgical services, such as Matins and Vespers, and is often sung during Christmas and Easter celebrations.
The Gloria is a joyous hymn of praise to God, expressing the glory of God, his peace on earth, and his mercy and salvation through Jesus Christ. It is a reminder of the Incarnation of Christ, and of his ultimate triumph over sin and death.