Mortal Sin?


Hi, I have a number of Catholic friends that do not believe that masturbation or premarital sex are mortal sins. Are they guilty of mortal sins if they themselves do NOT believe that they are committing mortal sins when they commit these acts? Thanks so much for your time and God bless you.


To reject a Church teaching on morals is a grave wrong. Masterbation of course a grave and objective wrong. No ifs, ands, or buts. Whether they are guilty of mortal sin would depend on their culpability.


Can you please tell me how someone’s culpability is determined? Thanks!


If they don’t know it’s a sin, then they are not committing a sin deliberately, so it wouldn’t be mortal.

The fact that they do not believe it to be a sin, and if they know what the Church teaches, then it is a mortal sin.


From the Catechism:

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.”

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.

2352 By masturbation is to be understood the deliberate stimulation of the genital organs in order to derive sexual pleasure. “Both the Magisterium of the Church, in the course of a constant tradition, and the moral sense of the faithful have been in no doubt and have firmly maintained that masturbation is an intrinsically and gravely disordered action.” “The deliberate use of the sexual faculty, for whatever reason, outside of marriage is essentially contrary to its purpose.” For here sexual pleasure is sought outside of "the sexual relationship which is demanded by the moral order and in which the total meaning of mutual self-giving and human procreation in the context of true love is achieved."
To form an equitable judgment about the subjects’ moral responsibility and to guide pastoral action, one must take into account the affective immaturity, force of acquired habit, conditions of anxiety or other psychological or social factors that lessen, if not even reduce to a minimum, moral culpability.

2396 Among the sins gravely contrary to chastity are masturbation, fornication, pornography, and homosexual practices.

Or are you looking for reasons other than specific Catholic teachings. Like the fact that sex is self giving to your spouse and masturbation is a selfish act. Masturbation (in almost every case) involves the sin of lust. Objectifying someone and using them for your own pleasure. Etc, etc, etc.


Do they know it is sin (by that I mean have they said that they know that it is) and just choose to not believe it. If they do know, that is full knowledge. If they know that it is wrong and they do it anyway, I am not sure how you could say that it is not a mortal sin, whether they believe it or not is irrelevant.


I think this question is rather interesting. Let me frame it in another way: If a person becomes convinced of moral relativism, can they still committ mortal sin?

For example, say these young people have been swayed by our culture to believe that no one, including the Church, can say what is right or wrong. Could they still sin mortally? Or have they been lead so far off track that their sins are only venial because of their improperly formed conscience?




The word for premarital sex is “fornication” in the bible. You can look it up and show them what St. Paul has to say about it.

1 Corinthians 6:9
"Or do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived; neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor homosexuals, nor thieves, nor the covetous, nor drunkards, nor revilers, nor swindlers, will inherit the kingdom of God."


Did you inform them it is a mortal sin? If you did… now that they heard the good news… and still commit it, then yes, they have committed mortal sin.

See the disease of relativism? Subjective belief does not change objective truth. It doesn’t matter what they believe… it doesn’t change what is true.


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