CIC 2760 Very early on, liturgical usage concluded the Lord’s Prayer with a doxology. In the Didache, we find, “For yours are the power and the glory for ever.”1 The Apostolic Constitutions add to the beginning: “the kingdom,” and this is the formula retained to our day in ecumenical prayer.2 The Byzantine tradition adds after “the glory” the words “Father, Son, and Holy Spirit.” The Roman Missal develops the last petition in the explicit perspective of “awaiting our blessed hope” and of the Second Coming of our Lord Jesus Christ.3 Then comes the assembly’s acclamation or the repetition of the doxology from the Apostolic Constitutions.

1 Didache 8, 2: SCh 248, 174.
2 Apostolic Constitutions, 7, 24, 1: PG 1,1016.
3 Titus 2:13; cf. Roman Missal 22, Embolism after the Lord’s Prayer.