O gladsome light - Hieromartyr Athenogenes

O gladsome light, O grace
Of God the Father's face,
The eternal splendour wearing;
Celestial, holy, blest,
Our Saviour Jesus Christ,
Joyful in thine appearing.

Now, ere day fadeth quite,
We see the evening light,
Our wonted hymn outpouring;
Father of might unknown,
Thee, his incarnate Son,
And Holy Spirit adoring.

To thee of right belongs
All praise of holy songs,
O Son of God, Lifegiver;
Thee, therefore, O Most High,
The world doth glorify,
And shall exalt forever.

---

Attributed to Hieromartyr Athenogenes  (c. 202 - 302) Palestine
Translated by Robert Bridges
Source: Wikipedia
Note: This is the Phos Hilaron (Ancient Greek: Φῶς Ἱλαρόν, Latin: Lumen Hilare) one of the oldest known Christian hymns outside the Bible.