The definition of mortal sin. Most of you aren't committing this!


Many people on CAF have asked questions here about whether one of their sins is mortal or not. I haven't seen a single one that met the Vatican's criteria for mortal sin in all my time on CAF. These folks wouldn't ask in the first place if they knew the definition. They'd be able to answer this question for themselves. Knowing what criteria a sin has to meet to be mortal can lend a good deal to a person's peace of mind. People get afraid they're damned over too slight of things.

Now I'm not saying it's not very important to fight venial sin. That is a very important battle everyone on Earth is called to fight. However, second-guessing ourselves all the time with questions over whether or not we've just damned ourselves can cause us to unnecessarily miss Communion and lose our peace, so I want people on these forums to know the mortal sin definition.

So I'm creating this thread, so that people will know it.

The main time people commit mortal sin a good deal are where they are in either habitual mortal sin or addictive mortal sin. Otherwise it's a stupid choice some Catholics might make, but an unusual one for someone who is making an effort in their life to do what the Church teaches. If a Catholic is trying to live faithfully to the Church's teachings and is fighting against venial sin, and is not engaged in some mortal sin addiction, they are very unlikely to commit a mortal sin. So most people here don't have to worry about it. Just keep fighting the venial sins and seeking to live in unity with God and His Church's teachings and you won't end up committing a mortal sin. It's if you let your spiritual life slide that you can become at risk. As Jesus said, "the one who perseveres to the end will be saved."

Here's the Catechism's definition of mortal sin, for anyone unaware :).

The mortal sin has to be deliberate, premeditated (not spur of the moment or accidental), committed with full knowledge of the nature of the sin and of one's transgression of God's Law, and it must be of grave matter -- a very serious sin, not getting impatient with one of your kids after a tough day at work and being unnecessarily sharp with them. We're talking adultery or idolatry here, major sins, not small ones. Such sins are always "grave matter."


Thanks for your post. My question is it seems to me that any sin disrupts our standing before God. The danger seems to me to be thinking of our sin as minor/major. While I understand that by their very nature some sin is much more serious than others, if you get down to it all sin is done out of self centered focus. In effect we think that we know better than God and we should be in charge of our actions. Also I think that our sins are also all premeditated. We make the choice to sin and as a result of that choice we have decided which in essence means it was premeditated. The only exception to this is the sin committed in ignorance which in my life experience is extremely rare. So my question is this; we know God can not be in the presence of sin. And we also know that any sin, no matter how minor, separates us from God. We also know that 99.99% of the time our sin is something we decide to do and is therefore premeditated. So then in reality are not all sins mortal?


No. There are such things as venial sins. For instance: the white lie. You lie with the intention of not hurting someone’s feelings. It is still a lie but the intention to do harm isn’t there. For instance, a child asks his Mom if his drawing is good. It isn’t but she’s not going to hurt his feelings. A man tells his wife she doesn’t look fat. A dinner guest tells the host the dinner was delicious when it was bland. A secretary tells a caller her boss is busy and he isn’t.

There is no malice in the above. Another criteria would be lack of knowledge that what one is doing is a sin. If he had know it was a sin, he wouldn’t have done it.

Venial sins still must be confessed.


[quote="aicirt, post:3, topic:177601"]

Venial sins still must be confessed.


No, they do not!


[quote="indyann, post:4, topic:177601"]
no, they do not!


why!! ;)


[quote="Indyann, post:4, topic:177601"]
No, they do not!


Actually, they do need to be confessed...though not necessarily in the confessional. The penitential rite during the Mass is sufficient for this.


You said MUST be confessed. The catechism states “strongly recommended”. Not the same thing. “Without being strictly necessary”

1458 Without being strictly necessary, confession of everyday faults (venial sins) is nevertheless strongly recommended by the Church.59 Indeed the regular confession of our venial sins helps us form our conscience, fight against evil tendencies, let ourselves be healed by Christ and progress in the life of the Spirit. By receiving more frequently through this sacrament the gift of the Father’s mercy, we are spurred to be merciful as he is merciful:60

So it is not true that venial sins MUST be confessed.


Thanks very much for this thread. As a new Catholic I've had a lot of questions about mortal and venial sin and this is very helpful. With most of the commandments, I'm at the point now where I can distinguish a mortal or venial sin... what constitutes grave matter and what doesn't. However, I'm still having trouble with one of the commandments. I am going to be speaking to my priest about this when I see him next but I hope its okay to also ask in this thread.

I'm having trouble understanding when lying becomes grave matter. I understand slander, calumny, etc is grave matter, because you are purposely harming another, but what about lies told about oneself? I'm thinking for instance, of the lies I used to tell as a teenager. I was in foster care, but I often would tell people I had this great family who loved me, and other wonderful (but untrue) things about my life because it was what I wanted to be true. I told huge, elaborate lies. I eventually grew out of doing this. I assume considering my circumstances and psychological state at the time, that this probably wasn't grave matter? Still, they were large, premeditated lies, and my examination of conscience booklet lists such as mortal sins.

Thanks if anyone wants to comment on this.


Thank you, Leif… for posting this reminder. It is helpful for the highly scrupulous souls (:rolleyes:).

God bless and HAPPY THANKSGIVING to all in the United States.


Okay. You win. It is “strongly recommeded” not a MUST. So we all agree: venial sins should be confessed. :thumbsup:


Hi Judith,

To me these seem just like “tall tales”, told by a child. You certainly meant no harm to anyone by making up stories.

You were trying to protect yourself, not intentionally cause harm. I bet your priest will say “Forget about them”.


OK thanks! That’s what I thought, but wasn’t sure. I assume also that similar kind of lies told by adults might fall under the same category? As in, the person has some psychological issues and isn’t really meaning to hurt anyone, so the intent really isn’t there, in that sense. Though one does hurt oneself, telling those lies. Its confusing… :shrug:

Sins other than lying are much easier for me to distinguish somehow… but thanks for your help. Its becoming a lot clearer to me overall.


The main issues discussed in the moral theology forum are abortion, contraception, sex outside marriage, masturbation, and homosexual activity.

These issues are so widely and frequently publicly talked about by the Church that I don’t believe anyone can claim they don’t know they are grave sins. Full knowledge simply means a person knows the Church teaches something is a grave sin even if the person does not understand why. In my view proably 99.999999% of people committing the above acts are committing mortal sins. They know they are grave sins and they commit them anyway.


I think that’s true for many people. One can imagine, though, there being some improperly catechized teenagers out there that grew up in liberal schools and don’t really know what their faith is.



I will only observe here, in general, that it is necessary to confess not only all the acts, but also improper touches, all unchaste looks, all obscene words, especially when spoken with pleasure, or with danger of scandal to others. It is, moreover, necessary to confess all immodest thoughts.

Some ignorant persons imagine that they are bound only to confess impure actions: they must also confess all the bad thoughts to which they have consented. Human laws forbid only external acts, because men only see what is manifested externally; but God, who sees the heart, condemns every evil thought: Man sees those things that appear; but the Lord beholdeth the heart? This holds good for every species of bad thoughts to which the will consents. Indeed, whatever it is a sin to do, it is also in the sight of God a sin to desire. I said, thoughts to which the will consents. *Hence, it is necessary to know how to determine when a bad thought is a mortal sin, when it is venial, and when it is not sinful at all. In every sin of thought there are three things: the suggestion, the pleasure, and the consent. *

i. The suggestion is the first thought of doing an evil action that is presented to the mind. This is no sin; on the contrary, when the will rejects it we merit a reward. "As often," says St. Antonine, "as you resist, so often you are crowned." Even the saints have been tormented by bad thoughts. To conquer a temptation against chastity, St. Bernard threw himself among thorns, St. Peter of Alcantara cast himself into an icy pool. Even St. Paul writes that he was tempted against purity. There was given me a sting of my flesh, an angel of Satan to buffet me." He several times implored the Lord to deliver him from temptation. 'For which thing thrice I besought the Lord that it might depart from me.' The Lord refused to free him from the temptation, but said to him: My grace is sufficient for thee." And why did God refuse to remove the temptation? That, by resisting it, the saint might gain greater merit. For power is made perfect in infirmity? St. Francis de Sales says that when a thief knocks at the door outside, it is a sure sign he has not yet got in; thus when the devil tempts us we have a strong proof that the soul is in the state of grace. St. Catharine of Siena was once assailed by the devil for three days with impure temptations; after the third day our Lord appeared to her in order to console her. She said to him: "Ah, my Saviour, where hast Thou been these three days?" He replied: "I was in your heart to give you strength to resist the temptation by which you were attacked." He then showed her that her heart had become purer than it was before.

  1. After the suggestion comes the pleasure. When a person is not careful to banish the temptation immediately, but stops to reason with it, the thought instantly begins to delight him, and give him pleasure, and thus draws the person on to give his consent to it. As long as the will withholds the consent, the sin is only venial, and not mortal. But if the soul does not then turn to God, and make an effort to resist the pleasure, it will easily go on to give its consent. "Unless," says St. Anselm, "a person repel the pleasure, it passes into consent, and kills the soul." A woman who had the reputation of a saint was tempted to sin with one of her servants; she neglected to banish the thought instantly, and so in her heart consented, and fell into sin, but only in thought. She afterwards fell into a more grievous sin, for she concealed in confession the complacency she had taken in the bad thought, and died miserably. But because she was believed to be a saint, the bishop had her buried in his own chapel. On the morning after her burial she appeared to him, enveloped in flames, and confessed, but without profit, that she was damned on account of the bad thought to which she had consented.

  2. The soul loses the grace of God and is condemned to hell the instant a person consents to the desire of committing sin, or delights in thinking of the immodest action as if he were then committing it. This is called morose delectation, which is different from the sin of desire.


My dear Christians, be careful to banish these bad thoughts, by instantly turning for help to Jesus and Mary. He who contracts the habit of consenting to bad thoughts exposes himself to great danger of dying in sin, for the reason that it is very easy to commit sins of thought. In a quarter of an hour a person may entertain a thousand wicked desires, and for every evil desire to which he consents he deserves hell. At the hour of death the dying cannot commit sins of action, because they are unable to move; but they can easily indulge sins of thought, and the devil suggests every kind of wicked thought and desire to them when they are in that state. St. Eleazar, as Surius relates, was so violently and frequently tempted by bad thoughts at the hour of death, that he exclaimed: " Oh, how great is the power of the devils at the hour of death!" The saint, however, conquered his enemies, because he was in the habit of rejecting bad thoughts; but woe to those who have acquired a habit of consenting to them! Father Segneri tells us of a man who during his life had often consented to bad thoughts. At the hour of death he confessed his sins with great compunction, so that every one regarded him as a saint; but after death he appeared and said that he was damned; he stated that he made a good confession, and that God had pardoned all his sins; but before death the devil represented to him that, should he recover, it would be ingratitude to forsake the woman who loved him so much. He banished the first temptation: a second came; he then delayed for a little, but in the end he rejected it: he was assailed by a third temptation, and consented to it. Thus, he said, he had died in sin, and was damned.

My brother, do not say, as many do, that sins against chastity are light sins, and that God bears with them.

  • St. Alphonsus Maria de Liguori, Bishop & Doctor of the Church

To abstain from sinful actions is not sufficient for the fulfillment of God’s law. The very desire of what is forbidden is evil.’

  • St. John Baptist de la Salle

The above shows that we must hate sinful desires with passion and fervor to overcome them, rather than fall into morose delectation, or the sin itself.


I've been wondering about this lately - my parents were atheists and I was taught as a child that there was no God and no such thing as sin, and was told that certain things were not sins that I now know were most certainly sins. At the time I suspected they were wrong, but my parents and friends and grandparents etc. said they weren't (like living with someone out of wedlock, for instance), so I finally believed them. Of course I knew that some people thought there was a God and such thing as sin, but whenever I asked people who believed those things to explain them to me, they refused (including relatives). :shrug:

So now I'm wondering - were sins that I committed before I came to understand the reality of God and of sin, mortal sins? Or were they only venial because of my ignorance? Or were they mortal, because I should have tried harder to find out the truth? :confused:

I don't suppose it matters much, since I've stopped committing them and they will all be washed away at my baptism. Still, I'd like to know.


You know? all those listed above are objectively mortal sin… but… addictions carry with it some form of denial, external and internal influences are complex, and we live eat and breathe in a strongly secular culture that seems “real,” and therefore I highly doubt that 99.999999% of the people committing the above sins are in FULL knowledge of the gravity of their actions.

The older I have become the more I have seen that objectively mortal sin is different from the individual committing the sin. Anything that goes against love is sin. And FULL knowledge is hard to measure.

The writers of the catechism provide for all those mitigations because of the complexity of the human heart and mind and weakness of the soul. So let’s stick with objective sin and try not to dump the word “mortal” on the questioners on CAF, especially the poor adolescents who frequently are wracked with guilt and fear over what… oooooh, masturbation!


Since you aren’t baptized yet, and are still in a state of original sin… mortal sin wouldn’t apply.

If someone was baptized but not taught anything… It’s difficult to know. Obviously people who don’t even admit mortal sins exist or ever heard of them, mortally sin and go to Hell.

And as we progress in our Christian journey we look back on our lives beforehand and more and more see where God’s grace was acting on our consciences and we were called not to sin, and we either obeyed or did not obey.


Did I read this right? A person has never heard of mortal sin, mortally sin and go to Hell? What happened to the “full knowledge” part? And what happened to “judge not, lest you be judged?”

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