Dist. 39, Art. 1, Q. 3
by St. Bonaventure
Source text: Public Domain Mark 1.0. English translation/apparatus/encoding: CC BY-NC 4.0, Wroot Press.
https://bonaventure.wrootpress.com/browse/3/d/39/q/bon-sent-III-d39-a1-q3
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### Question III. *Whether every perjury is a mortal sin.*

Thirdly it is asked whether every perjury is a mortal sin. And that it is so, it seems.

1. Augustine, in a certain sermon on the oath: «A false oath is pernicious, a true one perilous, none secure»; but what is pernicious is a mortal sin: since therefore every perjury is a false oath: therefore perjury is a mortal sin.

2. Likewise, what is directly against a precept and prohibition is a mortal sin; but perjury is directly against the prohibition of the second tablet and of the first: therefore it seems that it is always a mortal sin; for in both perjury is forbidden.

3. Likewise, contempt introduces a mortal sin; but everyone who perjures himself contemns the supreme Truth itself, while he adduces it as testimony of a falsehood: therefore every perjury is a mortal sin.

4. Likewise, a lie of itself, when it is serious, is a grave sin: since therefore the superadded oath draws the lie itself into another genus, it seems that any lie whatsoever becomes, through the superadded oath, a mortal sin.

**On the contrary:**

1. Just as it happens that someone lies in jest, so too it happens that someone swears something false; but what is done in jest is not done out of contempt: if therefore some perjury can be jesting, it does not seem that every perjury is a mortal sin.

2. Likewise, just as there is some lie which harms no one and benefits someone, so there can be some perjury; but such perjury proceeds rather from piety than from lust: since therefore lust is the root of every mortal sin, it seems that not every perjury is necessarily a mortal sin.

3. Likewise, just as it happens that someone speaks something false unpremeditatedly, so it happens that someone swears something false unpremeditatedly; but a sin is not mortal unless it be done from deliberation and consent: therefore not every perjury is a mortal sin.

4. Likewise, just as to take the name of God upon a falsehood conflicts with the precept of the Decalogue, so also to take it in vain; but not always, when someone takes the name of God in vain, does he sin mortally, as is plain concerning those who swear beyond necessity: therefore it seems likewise that he who takes the name of God upon a falsehood does not always sin mortally: therefore not every perjury is a mortal sin.

### Conclusion.

> Not every perjury is a mortal sin, namely when sufficient deliberation is lacking.

**I respond:** For the understanding of the foregoing it must be noted that perjury states two things, namely the swearing and the disorder. For perjury is a disordered and undue oath. Now an oath is threefold. One is deliberate and solemnized, as when witnesses swear upon the most holy Gospels of God in the presence of a judge. Another is deliberate, but not solemnized, when someone swears something in secret out of deliberation, intending to confirm it by the testimony of the divine Truth. But another is neither deliberate nor solemnized, as when someone swears in common speech, not attending to whom he invokes and for what, but out of a certain custom.

And according to this perjury can be committed in three ways; and if it be committed concerning a deliberate and solemnized oath, thus it is a grave and enormous sin, so much so that it even renders a man infamous. But if it be committed concerning an oath neither solemnized nor deliberate; thus it is not a mortal sin,

but venial, on account of this, that the tongue is set in a slippery place. — But if it be committed concerning a deliberate oath, though not solemnized; then a distinction must be made: for either he deliberates about the saying and about the oath, namely whether the saying is true, and whether it is to be confirmed by an oath; and then, if he perjures himself, he sins mortally. Or he deliberates about the saying only, whether it is true, yet not about the superadded oath; and then it can be a venial sin. Yet great care must be taken, because that venial [sin] is perilous and approaches very near to mortal sin. — It is therefore to be granted that not every perjury is a mortal sin, such as that which is not deliberate. The reasons also which show this are to be granted, although some of them do not necessarily compel.

1. But to that which is objected to the contrary, that a false oath is pernicious; it must be said that Augustine does not understand [it] generally of every oath, but of that which is done with deliberation; and of that it is true that it is a mortal sin.

2. To that which is objected, that every perjury directly conflicts with the divine prohibition; it must be said that that is not true of just any [perjury], but only of that which is done with full deliberation and consent. And if you object that every act of fornication and adultery conflicts with that precept: *You shall not commit adultery*, and therefore is a mortal sin; it must be said that the case is not alike concerning a word, which easily flies away, and concerning the perpetration of a carnal sin, since that act must always be subject to the rule of reason. Whence the work of the flesh is never consummated without a man being reckoned to have consented with full consent. Therefore it more generally conflicts with the prohibition than the act of perjury [does].

3. To that which is objected, that in every perjury there is contempt of the supreme Truth; it must be said that when someone swears out of a certain custom or in jest, not deliberating about the excellence of the Truth invoked in testimony, even though he can in some way be said to contemn, because he does not venerate as he ought; yet he does not properly contemn, because there is rather there a certain omission of due honor and negligence than the infliction of an affront. But if he were to do this out of deliberation, then without doubt he would sin grievously.

4. To that which is objected, that the oath draws the lie into another genus; it must be said that that is true when the oath is added with deliberation to the lie itself; for then it has the full account of an oath and draws [it] into another genus of sin. But when it is added apart from deliberation, then it is a certain aggravating circumstance, not necessarily drawing [it] into the genus of mortal sin, for the reason that that superadded oath does not introduce a full contempt of truth, nor is it destructive of truth itself, although in some way it disposes toward the contrary of truth, because custom frequently begets lust and contempt. Therefore perjury is greatly to be guarded against; and because, on account of the uncertainty of speech, perjury is frequently joined to an oath: hence it is that the oath itself, among Christian men, and most of all among the perfect, ought to be very rare, according to the counsel of Ecclesiasticus, the twenty-third [chapter], who says: *Let not your mouth become accustomed to swearing*, for there are many occasions [of falling] in it.

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