O Word Immortal of Eternal God

O Word immortal of eternal God,
Only begotten of the only Source,
For our salvation stooping to the course
Of human life, and born of Mary’s blood.
In equal honor with the Holy Ghost,
And with th’eternal Father glorified.

Sprung from the ever virgin womanhood
Of her who bare Thee, God immutable,
Incarnate, made as man with man to dwell,
And condescending to the bitter Rood;
In equal honor with the Holy Ghost,
And with th’eternal Father glorified.

Save us, O Christ, our God, for Thou hast died
To save Thy people to the uttermost,
And dying tramplest death in victory;
One of the ever blessèd Trinity,
In equal honor with the Holy Ghost,
And with th’eternal Father glorified.

Author: St. John of Damascus

Year: 750

This is an English translation of a Greek Canon for the Midnight Office (or Orthros) by St. John of Damascus (c. 675–749). The most common English version is by John Mason Neale (1862), but the original lyrics are by the 8th-century saint. Alternate attributions sometimes credit the translator, but the question asks for the author of the words.