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

The Introït comes from the Book of Wisdom (18:14-15), which in its literal meaning, relates the coming of the exterminating angel in the middle of the night to slay the first-born of Egypt, oppressors of the people of Israel. "While all things were in quiet silence, and the night was in the midst of her course, Thy almighty Word, O Lord, came down from heaven from Thy royal throne." To which is added a verse of Psalm 92: "The Lord hath reigned, He is clothed with beauty: the Lord is clothed with strength, and hath girded Himself."

The Gradual respond is take from Psalm 44: "Thou art beautiful above the sons of men: grace is poured abroad in Thy lips. My heart hath uttered a good word, I speak my words to the king: my tongue is the pen of a scrivener, that writeth swiftly."

The Alleluia repeats Psalm 92, which during this time has become the special canticle of the inauguration of the new messianic kingdom.

The antiphon of the Offertory is the same as for the Second Mass of Christmas.

The antiphon of the Communion is taken from the Gospel (Mt. 2:20), but from a different passage than the Gospel of this day: "Take the Child and His mother, and go into the land of Israel: for they are dead who sought the life of the Child."