“Phos Hilaron” (O Gladsome Light)

(c. 3rd–4th century, early Christian hymn)
Often considered one of the oldest known Christian hymns still in use.

O Gladsome Light,
Of the holy glory of the immortal Father,
Heavenly, holy, blessed Jesus Christ:
Now that we have come to the setting of the sun,
And behold the light of evening,
We praise God: Father, Son, and Holy Spirit.
For meet it is at all times to worship Thee
With voices of praise,
O Son of God and Giver of life;
Therefore all the world doth glorify Thee.