Today is the Octave Day of the Epiphany, it is of greater double rite. The lessons in the second and third nocturn of mattins, and the Gospel at Mass, are concerned with the baptism of Christ in the Jordan.
At Mattins yesterday the beginning of the first Epistle of St. Paul to the Corinthians was read that belongs to the Sunday within the Octave but is displaced by the assignment of the Feast of the Holy Family to that Sunday. This epistle is continued today. (Yesterday, also, the Mass of the Sunday was 'resumed' with Gloria, second collect of the Octave, third of the BVM, Credo, preface and communicantes of the Epiphany.) In the Office of the Octave Day everything is said as on the Epiphany itself except in verse Domine, labia me, invitatory and hymn begin mattins as usual. The lessons in the first nocturn are Omnino auditur (of the Tuesday after the Sunday after the Epiphany). In the third nocturn the antiphon Homo natus is sung with the psalm Fundamenta. Festal psalmody is used for mattins and all the Hours. At Lauds, and the Hours, the collect is proper to the day.
At Mass the Gloria is sung and the orations and Gospel are proper to the day. The Credo is sung, the preface and communicantes are of the Epiphany.
Vespers are of the Octave, with the proper collect of the Octave Day. Commemoration is made of the following Offices of St. Hilary of Poitiers and St. Felix.
In the liturgical books of 1962 the Octave Day has been renamed as the Commemoration of the Baptism of the LORD. As a second class feast it does not have first Vespers unless it falls on a Sunday. Whilst festal psalmody is used at mattins and lauds the ferial psalter is used at the Hours. The Doxology of the Epiphany is omitted at the hymns of the Hours. Mass is textually the same as in the Old Rite except the communicantes of the Epiphany are omitted. Vespers are without any commemorations.