The situation

According to Catholicism, during the Consecration, if for some reason, the priest consecrated only one of the species validly, would that configure an imperfect Sacrifice or the Sacrifice wouldn't even take place?

Some examples I'm thinking to achieve this situation:

  • Using a valid matter for only one of the species (e.g. bread and cider or barley bread and wine)
  • Using a valid form for only one of the species (e.g. making a mistake on Words of Institution of one of the species)
  • A priest who dies in the middle of the Consecration

I think is safe to say that the second example is the most common way such a thing could happen. And that being the case, it's totally possible for someone discover the possible invalidity, which is exactly what is in question, as it is happening. Take that as the general situation for this question.

My research

Catholic Encyclopedia

In my research about it, I came to this article about the Sacrifice of the Mass from The Catholic Encyclopedia (New York, 1911). There are two important parts (emphasis mine) that seem to answer my question:

The existence of the Mass

[...] Furthermore, the unbloody Sacrifice of the Eucharistic Christ is in its nature a transient action, while the Sacrament of the Altar continues as something permanent after the sacrifice, and can even be preserved in monstrance and ciborium. Finally, this difference also deserves mention: communion under one form only is the reception of the whole sacrament, whereas, without the use of the two forms of bread and wine (the symbolic separation of the Body and Blood), the mystical slaying of the victim, and therefore the Sacrifice of the Mass, does not take place.

The constituent parts of the Mass

[...] Not only older theologians such as Frassen, Gotti, and Bonacina, but also later theologians such as Schouppen, Stentrup and Fr. Schmid, have supported the untenable theory that when one of the consecrated elements is invalid, such as barley bread or cider, the consecration of the valid element not only produces the Sacrament, but also the (mutilated) sacrifice. Their chief argument is that the sacrament in the Eucharist is inseparable in idea from the sacrifice. But they entirely overlooked the fact that Christ positively prescribed the twofold consecration for the sacrifice of the Mass (not for the sacrament), and especially the fact that in the consecration of one element only the intrinsically essential relation of the Mass to the sacrifice of the Cross is not symbolically represented. Since it was no mere death from suffocation that Christ suffered, but a bloody death, in which His veins were emptied of their Blood, this condition of separation must receive visible representation on the altar, as in a sublime drama. This condition is fulfilled only by the double consecration, which brings before our eyes the Body and the Blood in the state of separation, and thus represents the mystical shedding of blood. Consequently, the double consecration is an absolutely essential element of the Mass as a relative sacrifice.

But just before this last citation, it actually is preceded by a disclaimer:

While the Consecration as such can be shown with certainty to be the act of Sacrifice, the necessity of the twofold consecration can be demonstrated only as highly probable.

Summa Theologiae

I tried to find something about it in the Summa, and the best I could get was a response where St. Thomas describes that once the consecration has started it should be finished, even requiring another priest to do it if necessary. But, this could be a necessity in terms of proper way to celebrate Mass, not that it would not be a valid Sacrifice, at least that's how it seems to me. Also, @Geremia remembered me about Missal's De Defectibus which proposes basically the same thing.

If the priest be stricken by death or grave sickness before the consecration of our Lord's body and blood, there is no need for it to be completed by another. But if this happens after the consecration is begun, for instance, when the body has been consecrated and before the consecration of the blood, or even after both have been consecrated, then the celebration of the mass ought to be finished by someone else. Hence, as is laid down (Decretal vii, q. 1), we read the following decree of the (Seventh) Council of Toledo: "We consider it to be fitting that when the sacred mysteries are consecrated by priests during the time of mass, if any sickness supervenes, in consequence of which they cannot finish the mystery begun, let it be free for the bishop or another priest to finish the consecration of the office thus begun. For nothing else is suitable for completing the mysteries commenced, unless the consecration be completed either by the priest who began it, or by the one who follows him: because they cannot be completed except they be performed in perfect order. For since we are all one in Christ, the change of persons makes no difference, since unity of faith insures the happy issue of the mystery. Yet let not the course we propose for cases of natural debility, be presumptuously abused: and let no minister or priest presume ever to leave the Divine offices unfinished, unless he be absolutely prevented from continuing. If anyone shall have rashly presumed to do so, he will incur sentence of excommunication."

Summa Theologiae, Tertia Pars, Q. 83, A. 6

Priests/Theologians opinions

A good priest that I trust (friend of mine), said that such a case would configure a "gravely injured Sacrifice". So another similar opinion to the theologians quoted before (mutilated Sacrifice).

I also asked another priest online and he said that the sacrifice would not happen in this case.

I addressed this question directly to other trusted individuals, and still waiting a response. Will answer myself if I encounter something clear about this situation.

Concluding questions

  • Is there anything said about this by the magisterium (even if indirectly)?
  • Is there an actual answer to this question, or it's a disputed thing among theologians?
    • Basically, can it be answered (with certainty) at all?

If we can arrive at a definitive conclusion, and it is that the Sacrifice doesn't take place, then, it would follow that in principle it would not be enough to fulfill the Sunday obligation if that was the case, right?

Take into consideration the example I proposed that is most probable, where the priest commits an error in the form unintentionally, and anyone who notices does so as it happens. Then, anyone who's ignorant of the deficiency in the form (either by not knowing it, or knowing but not noticing the deficiency) would not be liable. That's not in question.

But consider then a well informed Catholic who noticed the error. How far the Sunday obligation would impel them to go to another celebration? Only if they have the possibility to do so? Having planning other activities would be enough to say they can't?

I know that if it happened to me, I would do my best to go to a another celebration out of Love of God, and because of the uncertainty that led me ask this question. But it seems to me that someone who did their part trying to participate the Sacrifice of Mass, even if it was invalid and they were well informed to notice that when it happened, they couldn't be liable for a mistake of the priest. Am I right about it?

  • 1
    "it would follow that it would not be enough to fulfill the Sunday obligation if that was the case" ordinarily, an obligation is satisfied if the person acts in good faith according to their knowledge, so if you knew that Fr Smith didn't consecrate correctly and intentionally chose his Mass for your Sunday obligation, you would be at fault for not meeting it. If you were ignorant that the Mass lacked validity, you wouldn't be liable for failing to meet the obligation
    – eques
    May 9, 2023 at 14:14
  • Sure, knowing that such deficiency happens routinely and intentionally choosing it because of that would certainly be a sin against the precept of the Church. But I think that is almost unreasonable, the most common situation I can see it happening is a mistake from the priest. And sure, someone who is ignorant that the Mass lacked validity wouldn't be liable for failing to meet the obligation. I would also argue that even someone who notice the lack of validity and is unable to go to another celebration wouldn't be liable either, but would someone who knows and could go be liable? May 9, 2023 at 16:54
  • If you know it's invalid, you cannot choose to go because that means you are willfully participating in a sacrelige. Your obligation would presumably cease in such case if there were no knowingly valid Masses within a reasonable distance.
    – eques
    May 9, 2023 at 17:01
  • Unless you know that such a mistake happen routinely, it's impossible to foresee that a priest will commit a mistake that will render the sacrament invalidly. It's certainly possible to know it was invalid at the moment of the consecration when the mistake happened May 9, 2023 at 17:05
  • If you observe it being invalid and couldn't reasonably go to another Mass, not liable, sure. The point is you have to be acting in good faith; willfully attending an invalid liturgy is not good faith.
    – eques
    May 9, 2023 at 20:31

1 Answer 1


This is an interesting question because the separate consecrations of the bread and wine represent in an unbloody manner the sacrificial immolation of Christ, where His blood and body were separated on the cross.

Pohle-Preuss, The Sacraments: A Dogmatic Treatise (vol. 2): The Holy Eucharist, pt. 3, ch. 2, §1, art. 2 "The consecration as the real sacrificial act":

b) While the Consecration as such can be shown with certainty to be the act of sacrifice, the necessity of a twofold Consecration can be demonstrated only as highly probable.

α) Christ said at the Last Supper, after consecrating both bread and wine: “Do this for a commemoration of me.” It is extremely probable that this mandate referred to the validity, and not merely to the licitness, of the sacrificial action.

Moreover, the Mass, as a relative sacrifice, is essentially a representation of the bloody Sacrifice of the Cross. Since it was no mere death from suffocation that Jesus suffered, but a bloody death, in which His veins were emptied of their blood, this condition of separation must receive visible representation on the altar. This condition is fulfilled only by the double Consecration, which brings before our eyes the Body and Blood in the state of separation and thus represents the mystical shedding of the Blood. It is this consideration that suggested to the Fathers the idea, which was adopted into some liturgies, of the double Consecration as a two-edged “mystical sword.” Thus St. Gregory of Nazianzus says: “Hesitate not to pray for me, … when with bloodless stroke thou separatest the Body and Blood of the Lord, employing speech as a sword.” {Ep., 171 [240] ad Amphil. [CLXXI] (Migne, P. C., XXXVII, 282).}

Related: The 1957 Missal's De Defectibus ("Defects in the Celebration of the Mass") contains this statement about what to do if a priest dies after consecrating the bread but before consecrating the wine:

  1. If before the Consecration the priest becomes seriously ill, or faints, or dies, the Mass is discontinued. If this happens after the consecration of the Body only and before the consecration of the Blood, or after both have been consecrated, the Mass is to be completed by another priest from the place where the first priest stopped, and in case of necessity even by a priest who is not fasting. […]
    Si Sacerdos ante consecrationem graviter infirmetur, vel in syncopen inciderit aut moriatur, praetermittitur Missa. Si post consecrationem Corporis tantum, ante consecrationem Sanguinis, vel utroque consecrato id accidit, Missa per alium Sacerdotem expleatur ab eo loco ubi ille desiit, et in casu necessitatis etiam per non jejunum. […]
  • Reading the exactress of the Canon Law reminds me of the Book of Leviticus
    – Fomalhaut
    May 10, 2023 at 0:21
  • @Lisramic It's liturgical law.
    – Geremia
    May 10, 2023 at 0:26
  • thank you for the correction.
    – Fomalhaut
    May 10, 2023 at 4:51
  • I've read some parts of the Missal's De Defectibus (that being one of them) some time ago and forgot it could be useful for this question. But that excerpt only shows that once the consecration is initialized, the celebration should be properly continued. It does not address the question whether or not such a mass would be valid or not. It for sure indicates the necessity of the double consecration, but to me, it could as well be just a requirement as a matter of discipline (how to properly celebrate the Mass) not as a matter of validity. Correct me if I'm wrong. May 10, 2023 at 13:53
  • @PatrickBard You're right. That's why I wrote "Related". It doesn't directly bear on your question, but it does show the importance of the double consecration. Pohle says "the necessity of a twofold Consecration can be demonstrated only as highly probable" (which is the lowest grade of the theological notes).
    – Geremia
    May 11, 2023 at 0:33

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .