Ember Friday in Advent is a greater ferial day of simple rite. Its liturgical colour is violet. The Vigil of St. Thomas is not commemorated in the Office.
At Mattins the invitatory is Prope est and the Office hymn is Verbum supernum. Mattins has a single nocturn of twelve psalms (Pss. 80, 81, 82, 83, 84, 85, 86, 87, 88, 93, 95 & 96). The lessons are taken from a homily of St. Ambrose on St. Luke's Gospel. The lessons are all significantly longer than those found in the later editions of the Breviary to the extent that the text of the third lesson is entirely absent from the later books.
At Lauds the antiphons Constantes estote etc are sung with Pss 50, 142, 62-66, Domine audivi and 148-149-150. After the antiphon on the Benedictus, Ex quo facta est etc., is repeated the ferial preces are sung with the choir kneeling. The preces include the psalm De profundis.
At Prime the antiphon Constantes estote is sung with psalms are Pss. 53, 21, 118(i) and 118(ii). The ferial and Dominical preces are sung, kneeling at Prime and the shorter set of ferial preces at the other Little Hours.
Mass is sung after None. The texts are proper, the introit being Prope es tu etc. The second collect is of the Vigil of St. Thomas, the third collect isDeus, qui de beatae . The dismissal is Benedicamus Domino sung by the deacon facing the altar. The ministers wear violet folded chasubles. With the celebration of the Eucharist the Office of the Ember Day ends.
Vespers are first Vespers of the feast of St. Thomas the Apostle. The antiphons Hoc est praeceptum meum etc are sung with psalms 109, 110, 111, 112 & 116. The Office hymn is Exsultet caelum laudibus. The antiphon on the Magnificat is proper to the feast, Quia vidisti me etc. After the collect of the feast the Advent feria is commemorated with the Great 'O' Antiphon appointed for the 20th December O clavis David and the collect of the preceding Sunday. At Compline the preces are omitted.