Tu Trinitatis Unitas

Thou Trinity in Unity
Who Rulest all things mightily,
Bow down to hear the songs of praise
Which we they watchful servants raise,

When in the lingering peace of night
We wake to vigil, then in might
Of instant prayer O let us win
They healing balm for wounds of sin.

If, by the wiles of Satan caught,
We should in darkness sin in aught,
Do thou by grace, like light of day
From heaven come, purge it away.

Let naught impure our bodies stain,
No laggard sloth our souls detain,
No taint of sin our spirits know,
To chill or quench their inward glow.

Wherefore, Redeemer, grant that we
fulfilled with thine own light may be;
That in our course, from day to day,
By no misdeed we fall away.

O Father, that we ask be done
Through Jesus Christ, thine only Son,
Who with the Holy Ghost and thee,
Shall live and reign eternally. Amen

Attributed to Pope St. Gregory the Great (540-604)