This hymn is used for Matins during Easter from Low Sunday (Divine Mercy Sunday) to Ascension in the Extraordinary Form of the Roman Breviary. It is an option for use for Vespers on ferial days during Easter after the Octave and until Ascension in the Ordinary form.
This is the text as it appears in Hymns Ancient and Modern (1867):
O Christ, the Heavens’ Eternal King,
Creator, unto Thee we sing;
With God the Father ever One,
Co-equal, co-eternal Son;
Thy Hand, when the first the world began,
Made in Thine Own pure Image man,
And linked to fleshly form of earth
A living soul of heavenly birth.
And when the envious, crafty foe
Had marred Thy noblest work below;
Thou didst our ruined state repair
By deigning flesh Thyself to wear.
Once of a Virgin born to save,
And now new-born from death’s dark grave,
O Christ, Thou bidd’st us rise with Thee
From death to immortality.
Eternal Shepherd, Thou art wont
To cleanse Thy sheep within the Font,
That mystic bath, that grave of sin,
Where ransomed souls new Life begin.
Divine Redeemer, Thou didst deign
To bear for us the Cross of pain;
And freely pay the precious price
Of all Thy Blood in sacrifice.
Jesu, do Thou to every heart
Unceasing Paschal joy impart:
From death of sin and guilty strife
Set free the new-born sons of Life.
All praise be Thine, O risen Lord,
From death to endless life restored;
All praise to God the Father be,
And Holy Ghost eternally. Amen.
Words: Anonymous, ca. 6th Century; tr. by the compilers of Hymns Ancient and Modern, 19th Century.
Tune: “Church Triumphant” James W. Elliott, 1874.
The original Latin text (Rex Sempiterne Caelitum) of this hymn may be found here .