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

Today the Introït is taken from Psalm 118 which, because of its initial verse-Beati immaculati in via-had a processional application at Rome, such that it was sung on the afternoon of Good Friday during the stage of the procession going from the Lateran to the "Sessorian" Basilica (Holy Cross). "Thou art just, O Lord, and Thy judgment is right; deal with Thy servant according to Thy mercy."

The Gradual is the same as for the Wednesday of the "great scrutiny" (the fourth week) of Lent, and it is borrowed from Psalm 32. Whether a fortuitous coincidence or an insightful choice, it continues the idea which was begun in the reading of the Apostle, because he calls blessed the Christian people whose Lord is the Most High.

The verse of the Alleluia comes from Psalm 101 and serves as prelude to almost all the solemn prayers of the Church: "O Lord, hear my prayer, and let my cry come to Thee."

The versicle for the Offertory is taken from Daniel (9:17-18), and reflects the state of soul of the Romans during the high Middle Ages, when the Eternal City was continuously exposed to the assaults of the Lombards: "I prayed to my God, saying: Hear, O Lord, the prayers of Thy servant; show Thy face upon Thy sanctuary, and favourably look down upon this people upon whom Thy name is invoked, O God."

The verse for the Communion is borrowed from Psalm 75: "Vow ye, and pray to the Lord your God, all you that round about Him bring presents: to Him that is terrible, even to Him who taketh away the spirit of princes; to the terrible with all the kings of the earth."