When it is said
Sung at the Divine Liturgy once everyone has received Communion.
The priest turns to the people with the cup and says “Always, now and ever, and to the ages of ages.” The choir answers “Amen” and sings this hymn.
On Holy Thursday “Of Your mystical supper” is sung in its place.
Where it comes from
No author known
First sung in AD 624
The liturgy scholar Robert Taft quotes the Paschal Chronicle on when this hymn began. Its entry for May AD 624 tells how the hymn was first sung that month in Constantinople, under Patriarch Sergius, once everyone had received Communion. The clergy were then about to carry the cups, plates and other holy vessels back to the room where they were kept.
Robert Taft, “The Evolution of the Byzantine Divine Liturgy”, quoting the Paschal Chronicle
The end of a psalm
Its first words echo Psalm 71:8, where the psalmist’s mouth is filled with God’s praise all day long. From the Paschal Chronicle’s account, Taft concluded that in AD 624 a whole psalm was sung while people received, and this hymn was added to close it. The priest’s “Always, now and ever” just before it is what is left of that psalm’s closing words of praise.
Robert Taft, “The Evolution of the Byzantine Divine Liturgy”
The Scripture in it
My mouth is filled with Your praise and with Your splendor all day long.
Then my tongue will proclaim Your righteousness and Your praises all day long.
Bible text: Berean Standard Bible, public domain.
In Greek
Πληρωθήτω τὸ στόμα ἡμῶν αἰνέσεως, Κύριε, ὅπως ἀνυμνήσωμεν τὴν δόξαν Σου,
ὅτι ἠξίωσας ἡμᾶς τῶν ἁγίων Σου μετασχεῖν μυστηρίων·
τήρησον ἡμᾶς ἐν τῷ Σῷ ἁγιασμῷ, ὅλην τὴν ἡμέραν μελετῶντας τὴν δικαιοσύνην Σου.
Ἀλληλούϊα, ἀλληλούϊα, ἀλληλούϊα.