December 21st - The Fourth Sunday of Advent

Today is the fourth Sunday of Advent, it is of semi-double rite. The feast of St. Thomas the Apostle is transferred to tomorrow.

At Mattins in the first nocturn psalms 1, 2, 3, 6, 7, 8, 9, 10, 11, 12, 13 & 14 are sung. The lessons are from Isaiah (as in modern forms of the Breviary). In the second nocturn psalms 15, 16 & 17 are sung, the lessons are from St. Leo. In the third nocturn psalms 18, 19 & 20 are sung and the lessons are from a homily of St. Gregory. At Lauds the proper antiphons Canite tuba in Sion etc are sung. The psalms are 92, 99, 62-66, the Benedicite & 148-149-150. The antiphon on the Benedictus is proper to the 21st December, Nolite timere etc., and is sung in place of the antiphon Ave Maria etc.

At the Hours the antiphons of Lauds are sung. At Prime psalms 53, 117, 118(i) & 118(ii) are sung as is Quicumque vult. The Dominical preces are sung, standing.

Mass is sung after Terce. There is no Gloria. The second collect is Deus, qui de beatae the third for the Church or pope. The Creed is sung and the dismissal is Benedicamus Domino.

Vespers are first Vespers of the transferred feast of St. Thomas. The antiphons and psalms are taken from the Common of Apostles. The Sunday is commemorated with the Great 'o' antiphon O Oriens.