Summary of comments of this office by Dom Schuster, in his work L'année liturgique.

The Introït comes from Psalm 27: "The Lord is the strength of His people and the protector of the salvation of His anointed: save, O Lord, Thy people, and bless Thy inheritance, and rule them for ever."

The Gradual respond, is taken from Psalm 89; it is the same as the one for the third reading of the Ember Saturday of Lent: "Return, O Lord, a little; and be entreated in favor of Thy servants."

The versicle of the Alleluia is taken from Psalm 30, and develops the same theme as the preceding chant: "In Thee, O Lord, have I hoped, let me never be confounded."

At the Offertory, the same chant is sung as for Sexagesima Sunday; it is taken from Psalm 16. In it one sings of the grace by which God directs the movement of our free will in the observance of the divine law.

The versicle for the Communion comes from Psalm 26: "I will go round, and offer up in His tabernacle a sacrifice of jubilation; I will sing, and recite a psalm to the Lord."