This hymn is used for Matins on Saturdays throughout the year in the Extraordinary Form. It is used for Office of Readings on Saturdays of Weeks I & III during Ordinary Time in the Ordinary Form. It is also used for Matins on Trinity Sunday.
O Thou eternal Source of love!
Ruler of nature’s scheme!
In Substance One, in Persons Three!
Omniscient and Supreme!
For thy dear mercy’s sake receive
The strains and tears we pour,
And purify our hearts to taste
Thy sweetness more and more.
Our flesh, our reins, our spirits, Lord,
In thy clear fire refine;
Break down the self-indulgent will;
Gird us with strength divine.
So may all we, who here are met
By night thy name to bless,
One day, in our eternal home,
Thine endless joys possess.
Father of mercies! hear our cry;
Hear us, coequal Son!
Who reignest with the Holy Ghost
While ceaseless ages run.
Words: Anon. 7th C.; tr. Fr. Edward Caswall, 1849.
Tune: “Summæ Deus Clementiæ” Gregorian Chant, Mode IV, traditional.
The hymn takes the following form on Trinity Sunday:
O Thou eternal Source of love!
Ruler of nature’s scheme!
In Substance One, in Persons Three!
Omniscient and Supreme!
Be nigh to us when we arise;
And, at the break of day,
With wakening body wake the soul,
Her meed of praise to pay.
To God the Father glory be,
And to his only Son;
The same, O Holy Ghost! to Thee,
While ceaseless ages run.
The original Latin text may be found here.
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