What is a mortal sin?

I know the three steps but i don’t know if i understand them 100%. Im often wondering if i commited the mortal sin or not. I don’t know if im 100% aware of the seriousness of the matter. Do you really have to just pause and say, well this is a mortal sin but im still going to do it, or are there other ways?

Grave matter, full knowledge, and deliberate consent.

Could you define deliberate constent more detailed?

From the Catechism of the Catholic Church:

1855 Mortal sin destroys charity in the heart of man by a grave violation of God’s law; it turns man away from God, who is his ultimate end and his beatitude, by preferring an inferior good to him.

Venial sin allows charity to subsist, even though it offends and wounds it.

1856 Mortal sin, by attacking the vital principle within us - that is, charity - necessitates a new initiative of God’s mercy and a conversion of heart which is normally accomplished within the setting of the sacrament of reconciliation:

When the will sets itself upon something that is of its nature incompatible with the charity that orients man toward his ultimate end, then the sin is mortal by its very object . . . whether it contradicts the love of God, such as blasphemy or perjury, or the love of neighbor, such as homicide or adultery. . . . But when the sinner's will is set upon something that of its nature involves a disorder, but is not opposed to the love of God and neighbor, such as thoughtless chatter or immoderate laughter and the like, such sins are venial. 

1857 For a sin to be mortal, three conditions must together be met: “Mortal sin is sin whose object is grave matter and which is also committed with full knowledge and deliberate consent.”

1858 Grave matter is specified by the Ten Commandments, corresponding to the answer of Jesus to the rich young man: “Do not kill, Do not commit adultery, Do not steal, Do not bear false witness, Do not defraud, Honor your father and your mother.” The gravity of sins is more or less great: murder is graver than theft. One must also take into account who is wronged: violence against parents is in itself graver than violence against a stranger.

1859 Mortal sin requires full knowledge and complete consent. It presupposes knowledge of the sinful character of the act, of its opposition to God’s law. It also implies a consent sufficiently deliberate to be a personal choice. Feigned ignorance and hardness of heart do not diminish, but rather increase, the voluntary character of a sin.

1860 Unintentional ignorance can diminish or even remove the imputability of a grave offense. But no one is deemed to be ignorant of the principles of the moral law, which are written in the conscience of every man. The promptings of feelings and passions can also diminish the voluntary and free character of the offense, as can external pressures or pathological disorders. Sin committed through malice, by deliberate choice of evil, is the gravest.

1861 Mortal sin is a radical possibility of human freedom, as is love itself. It results in the loss of charity and the privation of sanctifying grace, that is, of the state of grace. If it is not redeemed by repentance and God’s forgiveness, it causes exclusion from Christ’s kingdom and the eternal death of hell, for our freedom has the power to make choices for ever, with no turning back. However, although we can judge that an act is in itself a grave offense, we must entrust judgment of persons to the justice and mercy of God.

I think people try to impose a ‘higher standard’ on ideas like ‘full knowledge’ and ‘deliberate consent’ when it comes to mortal sins, and I think they’re wrong.

If you’re driving a car, and you have been educated in driver education, read the book, passed the test, achieved the license, had a few years of experience under your belt, and you got into the habit of driving too fast, having ‘a couple of beers’, not bothering to check your tires, fluids, etc., and then you had a bad accident as a result, would the insurance company buy your claim that you 'didn’t fully KNOW" that the above were dangerous? Would they buy the idea that you didn’t ‘deliberately consent’ to doing those things every time you did them? I think that the ‘reasonable people standard’ (often used in court) would apply. A reasonable person would, in the scenario above, know that driving too fast, driving after drinking, and not properly maintaining a vehicle, could result in a bad accident, and that if you did those things, you were freely and deliberating choosing or consenting to do so.

Same with mortal sin. We don’t have to have the kind of ‘knowledge’ of a genius, nor the kind of deliberate consent taken after the kind of study one would give to a topic before taking, say, the LSAT. Just normal ‘full knowledge’ like a driver would have regarding driving, and consent like somebody who ‘takes risks’ knowing the consequences.

It is not complicated.

If you know the Church teaches that a particular act is of grave matter and you still go ahead and commit the act then you commit a mortal sin.

This is not correct Thistle.
“…You go ahead and commit the act” is not the same as “full consent”.

Many people have addictions and do things they know to be gravely wrong.
Even violently yelling/abusing one’s wife I would consider grave matter.
Yet many good Catholic husbands do exactly this do they not even though they want to stop.

To say one is destined to hell (“mortal sin”) immediately and after each occassion does not do justice to the scenario. Full consent is often lacking in cases of psychological or bodily addiction/compulsion. Such cases may well be venial.

However, whenever we are aware that “grave matter” is involved we should always seek confession on a regular basis. If compulsion/addiction is known to be in play then sdtandard confessional practice does not require confession immediately after each and every act.

Listen. We are talking about normal circumstances as you well know. Do I have to every time state “assuming no mental incapacity or coercion”???
Assuming no mental incapacity or coercion anyone who knows the Church teaches an act is of grave matter and goes ahead and commits the act then that is a mortal sin. It is not required they sit and think about about and decide to do it. As long as they know it is of grave matter then doing it is deliberate consent and a mortal sin.

It is not really about some “percentage”…

Grave matter, full knowledge and deliberate consent.

The Catechism has a good section on it.

Ones confessor can assist as well in ones case.

Thistle it would be great if you could let me decide what I know and don’t know, thanks :thumbsup:.

The view of deliberate consent and full knowledge you opine here cannot be said to come anywhere near matching the depth of understanding of these terms in moral theology that underpins the all too brief summary in the CCC.

I believe it misleading to our OP to leave him with the impression that things are anywhere near as simple and b&w as you are suggesting. Actually, the OP already suspects this and I am signalling that he is correct

The OP may like to research moral theology resources that differentiate between “human acts” and the “acts of a man”…

It is not complicated. Assuming no coercion or mental incapacity you commit a mortal sin if you commit an act you know the Church teaches is of grave matter. Deliberate consent does not mean pausing for a few minutes to think about the act before you commit it.
If you know an act is of grave matter and you do it anyway then you commit a mortal sin (assuming no coercion or mental incapacity!!).

Thistle your personal opinion here is unfortunately not well supported by mainstream Catholic Moral Theologians and would be regarded as a little extreme in Catholic Philosophy of Man 101 as taught at Catholic Universities/Seminaries.

Well the priests are the Confessors and all the ones I spoke to told me it is pretty straightforward. Assuming no coercion or mental incapacity (I now always insert this for your benefit), in other words under normal circumstances,o if a person knows the Church teaches an act is of grave matter and they go ahead and commit the act it is a mortal sin. I will go with the priests views against Catholic Philosphy of Man 101!!
In my opinion, trying to complicate things is another way of looking for a get out of jail free card and attempting to justify continuing to sin.

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