The music this day is remarkable for a number of reasons. This is not a Sunday, so there is no Asperges. And since there is no Asperges, we will sing the Introit (Nos autem) as the processional. Typically, the Introit consists of an antiphon followed by a verse from one of the psalms, which is then followed by the Gloria Patri, after which the antiphon is repeated. Today is unique for two reasons: 1) Of course, since we are in Passiontide, we omit the Gloria Patri, and 2) We have the possibility of singing thee additional verses from the psalm, each of which would be followed by the antiphon (Nos autem). How many verses we will sing will depend on the available time according to how long the prayers at the foot of the altar take. Note that they are abbreviated today with the psalm Judica me and the Gloria Patri omitted.
The priest is not wearing Violet (he will be wearing White) so you might imagine that Mass XVII is probably out, and so it is. The rubrics for the day suggest that if the Mass of the Holy Oils had been said in the morning, at which Mass IV would have been used, then we could sing Mass IX in the evening. Otherwise, Mass IV is suggested for the evening Mass, and that is indeed what we will sing.
Holy Thursday is special because, even though it falls in Holy Week, it is a time of rejoicing since it commemorates the institution of Holy Orders and the Blessed Sacrament of the Eucharist. In keeping with the somber side of things, the Kyrie is unaccompanied, but on the other hand, the Gloria is accompanied by the organ – the last time we will hear it until the Gloria at the Mass of the Paschal Vigil. The Gloria is also accompanied by a glorious ringing of the bells, but they too will disappear until the Gloria at the Mass of the Paschal Vigil. In place of the bells, you will hear the knocking of the clacker.
The Gradual (Christus factus est) is a recurring theme throughout Holy Week, and in particular, at Tenebrae. Given the dual nature of the feast, what follows on the Gradual? Certainly not an Alleluia! Not during Lent, and certainly not during Holy Week. A Tract? Not on such a day of rejoicing! So, what follows on the Gradual? Nothing! And that is a rarity indeed! We proceed directly from the Gradual to the Gospel.
There is no Credo because, even though it is a time of rejoicing, the day itself is a Feria, and the Credo is not said on days of Feria.
During the Washing of the Feet, the Schola will sing a number of antiphons. We will keep a close eye on the proceedings because as Father approaches the last of the Apostles, we must conclude with the other antiphons and start with the Ubi Caritas, which is mandatory.
The Gloria Patri is omitted at the Lavabo. At the Offertory, the Choir will sing a polyphonic version of what was sung at the Gradual (Christus factus est).
You will notice as we begin to sing the responses before the Preface that the tones are slightly different. There are three variations on the responses as there are three variations on the Preface itself: 1) the simple, or ferial tone, 2) the solemn tone, and 3) the more solemn tone. You will know that the more solemn Preface is coming (and it is exquisitely beautiful) as soon as you hear the more solemn responses prior. The Preface is that of The Holy Cross.
The character of the Mass has changed, and has now become more somber. This is very apparent as we sing the Agnus Dei. We repeat the phrase miserere nobis three times and do not sing dona nobis pacem.
The second Confiteor is omitted. At the Communion, the choir will sing Byrd’s Ave Verum, in honor of the Blessed Sacrament. The Schola will sing the antiphon and several verse from Psalm 22 (The Lord is my Shepherd), which is suggested for the day.Instead of the Ite Missa est, Father will sing Benedicamus Domino. There is no Last Blessing and no Last Gospel. As soon as Mass is ended, the Blessed Sacrament will be translated in procession to the Altar of Repose. We will sing the Pange Lingua in procession, repeating verses 2 through 4 until we arrive at the Altar of Repose, at which time we will sing verse 5. The procession will return to the Church for the Stripping of the Altar during which the Schola will solemnly chant the now familiar Psalm 21 – Deus, Deus meus.