Failure to Commit a Mortal Sin



Does one commit a mortal sin if one is prevented from doing so?

For example: a man plans to rob a bank and kill everyone in the bank. He arrives at the bank armed and ready to act; however, when he arrives the bank has closed due to a power failure. Has the man committed a venial sin, mortal sin, or has he not sinned at all?




Mortal sin is already involved in deliberately choosing to do so - even if one is prevented from doing it.

Mortal sin is where there is grave matter, full knowledge and deliberate consent -if such is present though one is prevented from carrying into external action the sin - *there is already mortal sin. *

Mortal sin is not only regarding exterior actions.


Oh man, I hate when that happens. :stuck_out_tongue:


If you try to stab someone but the blade breaks instead then you’ve still committed a mortal sin.


The concept of “thought-crime” raises its ugly head again. How can the most horrible despotism combined with torture and brain-washing arrive at the same proposition as Christianity? Don’t you see that there is something wrong with this picture?


It doesn’t.



It’s not remotely the same thing at all. We’re not talking about fantasies or idle thoughts here. We’re talking about intent.

A more accurate comparison would be to the concept of an incomplete crime, not a thought crime. In our legal system, if you shoot someone, but you turn out to be out of ammo, you can be tried for attempted murder. If you had every intention of killing that person, but were prevented from completing the act, you are still considered guilty in court.

It’s the same principle in the spiritual life. Sin lies in the heart. If you had every intention of committing a grave sin, but were prevented from completing the act by outside circumstances, you are still guilty of sin.

Do you really not see the difference between that and punishing someone for having the wrong opinion of the government?


I’m not sure I agree with some of the responses here.

The bank robber is certainly not in a good place spiritually or morally. Would the robber’s culpability still be the same if his car hadn’t started and he never left the driveway of his home or perhaps if he misplaced the weapon he intended on using.

For a sin to be mortal three things need to be present: 1) Object is grave matter; 2) committed with full knowledge; 3) and deliberate consent.

In this case since murder or bank robbing is not committed at least one of the three requirements is not met. I’m not sure that travelling to the bank is enough to say the sin has been committed.

I would never argue that this bank robber is blameless and off the hook. He has plenty of issues to work through though.



Actually *all three *can be presumed in this story to be met - the choice to murder or robe the bank are both grave matter - that choice was made with full knowledge and with deliberate consent.

So yes - mortal sins occurred (all things being equal) way before he made it to his car or looked for his gun.


But see you’ve changed the wording of the Catechism. In the Catechism it says “committed” you’ve said “choice.” Those two words are not interchangeable nor are they synonymous.



What Bookcat is saying is the same as what Jesus said about how the one who lusts after a married woman has already committed adultery with her in his heart. The person who consciously decides to commit a sin has already committed the grave matter necessary for a mortal sin. The Catechism doesn’t say only external actions count as commiting a sin, and Christ himself is abundantly clear that internal desire is enough to condemn a person.

To be clear though, what we’re talking about isn’t the same thing as being tempted to commit robbery or adultery, or even seriously considering it. Neither of those are mortal sins. We’re talking about someone who freely decides that yes, he wants to rob that bank, and intends to do it. Just choosing that in itself is a mortal sin because that’s the very definition of sin - choosing something other than God. Putting our will above God’s.

Sin lies in the will. In the heart. That’s why you can’t accidentally commit a mortal sin. It takes a deliberate choice. Yes, actually going through with a murder and adultery is “worse” because someone else is involved and we are actively hurting them. If you repent from actually having committed a murder, that person is still dead and can never come back. But as far as our spiritual state goes, there is no difference. We still made the decision to reject God.

Does that make a little more sense?


Yes, I suppose that makes sense. Reading other parts of the Catechism brought that home to me. In this hypothetical situation this person, having not actually robbed a bank or murdered anybody, would take a step back and come to their senses and abandon all of their plans.



No I have not changed the wording of the Catechism. But yes it also uses the term “choice”. Mortal sin.

And it notes that sin can be in thought, desire etc.

Choice is how one begins to commit a mortal sin - choice.

Sin is committed (by choice) by the will long before any external action.

(Also note too that The Catechism is not intended to be an extensive work of moral theology.)


As soon as they will full knowledge gave deliberate consent - there was mortal sin. The committed the mortal sin of intending or choosing to murder or rob a bank. Even if they later repent and do not carry it into action - they have already committed a mortal sin that will need to be confessed.

Now being “tempted” to murder someone - or rob a bank - now that would be a different matter. One can be tempted without committing mortal sin.


We must’ve been looking at two different sections of the Catechism, since where I found the three requirements for mortal sin, explicitly used the word “commit” (paragraph 1857 I believe). A few paragraphs before mention that sin can indeed be committed in one’s heart. However, I believe the Catechism is deep enough to answer most questions, as it seems to have now.



Yes the Catechism is a very splendid work (saying that it is not a extensive work of moral theology or other kinds of theology- is not setting aside its splendor in what it is! I use it all the time).

“Commit” does not mean anything external needs to be done for a mortal sin to occur - it though involves a choice (an act of the will).

One can commit a mortal sin already by deciding to rob a bank. Or intending to.

One can commit a mortal sin already by desiring to murder someone or deciding to or intending to.

One can commit a mortal sin already by deciding to commit adultery.


If one is then prevented from carrying out into action ones choice - there was still mortal sin. One would still confess “I decided to murder a person but then was not able to” Or “I decided to murder someone but then later repented and did not”. Or “I decided to rob a bank - but there were too many cops so I did not and now I repent”…

Or* if is able to carry it into action* - then if one repents one would confess “I murdered a person”…or “I robbed a bank”.

(Such is again very different than just the tempting thought that could happen etc - where there was no act of the will endorsing it. )


Thanks for all the replies. I must admit I find them - scary.

To change the scenario: instead of finding the bank closed, the would be robber - approaching the bank - remembers a discussion on the Catholic Answers Forum that robbing a bank is a mortal sin. The would be robber then decides not to go through with the robbery and instead goes to St. Harold’s parish unemployment assistance program.

In this case the sin was not prevented but rather the would be sinner decided not to commit the sin. Is the would be robber still guilty of mortal sin?

Thanks again!


No it is not so scary…(aside from the fact that one can freely choose such evil…etc)

Difficult to say - I think that most people are going to know that robbing a bank or murder is VERY SERIOUS and even if they do not use the term “mortal sin” they know it is very serious offense against God.

But lets leave that example and simply say that:

Can a person decide to do X without the full knowledge needed to commit a mortal sin?


And can that person then realize - hey wait a minute - this thing I decided to do is actually a mortal sin - and Hey I do not want that to happen! And so repent and turn away from their former decision (without the needed knowledge) and thus not commit a mortal sin?


Or likewise - a persons thoughts might head in a particularly sinful direction - without that full knowledge and deliberate consent - and as soon as they realize what is happening - the nature of it - they do not consent but reject such. And thus do not commit a mortal sin.


Sorry, to say that “intent” is also a “sin”, even if it is not carried out - is the quintessential definition of “thought crime”.

And the secular approach makes a distinction. Attempted murder is NOT viewed as a murder.


But it is a crime nonetheless, a violation of the criminal law, just like intent to sin is a violation of God’s law.

DISCLAIMER: The views and opinions expressed in these forums do not necessarily reflect those of Catholic Answers. For official apologetics resources please visit