No, “Dies iræ” is not licit at a NOM requiem Mass
Adoremus, ceciliaschola.org, and others have tried to argue that “Dies iræ” (DI) is licit in Novus Ordo Masses, even though it’s not listed as a sequence in the liturgical books. Now, to my disappointment, the otherwise fine blog The New Liturgical Movement is reinforcing this claim. The reasoning goes like this:
a) DI is in the old rite, albeit having been rendered optional in 1967
b) the new rite is a reform of the old rite
c) nothing ever explicitly banned DI from the Mass
Adoremus talks a lot about how it is still in the current liturgical books as a hymn for the Office in the last week of the Church year - it’s an interesting observation, but it’s irrelevant. Lots of texts are hymns for the Office, but only 4 are given as sequences in the modern Roman Rite.
The trouble is that the norms - GIRM and Intro to the Lectionary mostly - spend very little time discussing sequences. Nothing talks about using texts that aren’t in the Lectionary as sequences; it is simply stated that the sequence is required on Easter and Pentecost, and optional otherwise. The norms take no time to say “only texts given as sequences are to be used as sequences”.
Through this loophole, well-meaning folks have sung “Dies iræ” at NOM funerals, with the justification that it is a traditional text etc.
The issue is that the same loophole fails to restrict the texts to be used as sequences. There’s nothing that says “only texts traditionally used in the Mass as sequences may be sung as sequences”. Therefore, I could, quite licitly, sing “Michael row the boat ashore” as a sequence. In fact, there’s nothing that says what the sequence is; therefore, I could quite reasonably get up and give an “extemporaneous sequence” that would, in effect, be a “pre-homily”.
It is the job of the norms to prevent bad ideas, be they held in good conscience or bad, from being implemented. If the intent of those who wrote the norms (ostensibly under the guidance of the Holy Spirit) was for DI to be allowed, they would have written in something about it. Otherwise, I only pray certain dioceses don’t discover the same loophole! A “pastoral necessity” to have unrhymed, conversational “sequences” (lectures) given by lay people?
For the record, other than that it is not normatively permissible, I think “Dies iræ” should be sung at requiem Masses. A comparison of this text with Protestant funerals (i.e. Bach’s cantata BWV106, “Gottes Zeit ist die allerbeste Zeit”) makes the doctrinal differences between Catholics and (most) Protestants concerning death and judgement strikingly apparent.
Also for the record, point b), about the new rite as a reform of the old rite. JP2’s letter that gave permission for bishops to give permission for the old rite explicitly forbade mingling of the old with the new rite. Fr. Joseph Gélineau went on record saying that the Roman Rite as it had been known was destroyed.