From a reader…
Recently at my parish, we had a retired priest say masses while our priest was away. In addition to improvising prayers during the Collect, he changed the wording of the Words of Institution. During the consecration of wine, he said something along the lines of, “This is the cup of the new covenant,” without ever mentioning the word “blood.” Did this invalidate the consecration? Furthermore, if it did, am I under moral obligation as a layperson to warn fellow parishioners that what they hope to receive as the Precious Blood of the Lord remains unconsecrated wine?
There are several issues here.
First, when I see descriptions including “along the lines of” instead of exact wording, my antennas wave.
However, you say that he did NOT say the word “Blood”.
It is possible to screw up or change some elements of the form and still validly consecrate, but if you don’t include the word “Blood” at all… then I say that isn’t a valid consecration. The Precious Blood was not consecrated.
That means that Mass was not celebrated.
If people receive a Host for Communion, they received the Eucharist. If they drank from an offered chalice… nope.
There are ramifications for the intention and the stipend for the Mass.
What to do about this?
Doing this once might be a mistake. Doing this regularly is another matter entirely. That would mean he means to do it.
I suppose the first thing would be to bring it up to a priest a the parish. If there isn’t one at all, ask the priest who is doing this about it. If he blows you off and keeps doing it, then he should be reported IMMEDIATELY to the local bishop and/or the Congregation for the Doctrine of the Faith. This is grave matter.
Fathers… STICK TO THE BOOK!