This hymn is used for Vespers & Matins on the Feast of the Holy Guardian Angels in the Extraordinary Form. It is used for Vespers on the same Feast in the Ordinary Form.
Praise we those ministers celestial
Whom the dread Father chose
To be the Guardians of our nature frail,
Against our scheming foes.
For, since that from his glory in the skies
Th’ Apostate Angel fell,
Burning with envy, evermore he tries
To drown our souls in hell.
Then hither, watchful Spirit, bend thy wing,
Our country’s Guardian blest!
Avert her threat ‘ning ills; expel each thing
That hindereth her rest.
Praise to the glorious Trinity, whose strength
This mighty fabric sways;
Whose glory spreads beyond the utmost length
Of everlasting days.
Word: St. Robert Bellarmine, ca. 16th C.; tr. Fr. Edward Caswall, C.O., 1849.
The original Latin text of this hymn may be found here.