Mortal sin and Church authority


Hello everyone,

I’m having a bit of trouble with mortal sin. I understand the scriptural and traditional basis for mortal sin. I also understand the three conditions for mortal sin. My question is what constitutes a “grave” issue or matter?

I had people tell me that eating meat on Fridays was a “grave” issue. I am finding difficulty in ascertaining what is “grave” and what isn’t. The Church doesn’t provide some canonical list of all the grave issues. I want to know what I need to mention at confession (grave issues, therefore mortal sins), and what I can confess personally through prayer and mass (non-grave isues, therefore venial sins).

So how do we find out what is considered grave? What documents do we use as the basis for this? The Ten Commandments? Canon law? Civic law? Gut feeling? Finally, when an issue is in dispute, who has the final authority to “declare” it as grave and thus impose mortal sin?

I know it’s a mouthful of questions, but I really appreciate the insight and charity here on this forum! Thanks a lot!


P.S.- If eating meat on Fridays is actually a grave issue, could someone please explain how it is? Thanks again!


From the CCC:

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.

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.” 132 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.

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.

Hope that helps…:wink:


It is best to consult the Catechism, a priest, or ask online if you have any specific sin in mind.

Here is an online searchable Catechism.

P.S.- If eating meat on Fridays is actually a grave issue, could someone please explain how it is? Thanks again!

It is grave matter ONLY in regards to it being a Church regulation. Eating meat is not by itself sinful. Drinking alcohol is not by itself sinful, it becomes sinful when you do it with the intention of getting drunk.

The authority of the Church to set temporary dietary restrictions at certain times goes all the way back to the Council of Jerusalem in Acts 15 (esp verse 20). These regulations can be changed at any time but are usually created to promote spiritual growth (eg fasting).


Here is a good examination of conscience that goes by the 10 commandments here



The Church has long held, that in order to sin gravely you, must have full intention. That is to realize your sin and then commit to it. In legal terms it would be premeditation.

Sin is not a mistake in judgement, but a well thought out plan.

If you commit a sin not knowingly, it is not grievous.

Full intention must be in the action.

I believe Hell well may be a very empty place. I don’t believe, most of us sin with full intention often.


It is my understanding that although a sin may deal with grave matter, it is not always a mortal sin. As you said, there are three requirements for it to be deemed mortal. So, if a sin is of grave matter, but is not done with full knowledge or with full consent, it is not a mortal sin, although still a grave matter. It would then probably be deemed venial.

Feel free to correct me, but I thought that is how it worked.

closed #8

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