So How Hard is it to Commit a Mortal Sin?


I did a thread on this a while ago but it didn’t achieve my objective.

I am from a background that takes the position that, basically, anything you do is a mortal sin. You can’t breathe or exist without doing something that would cut off your relationship with God - that we, by nature, deliberately cut off our relationship with God. Hence the need for overpowering grace that subsumes all human faults: cooperation is irrelevant, so faulted is man, etc. Enough on that.

In contrast I just read a thread on which it seemed people are taking the position it is almost impossible to commit a mortal sin. According to this viewpoint you have to go way out of your way with full deliberation to do it. Since we love Jesus, we would never do such a thing with full consent. We would have to be crazy to sin mortally, meaning that we have an insanity defense, so it is not mortal sin.

So I look at this, and think: maybe I have no mortal sin? Maybe it is so hard to do that all I have done is venial, regardless of how heinious it was, because some part of me, at least, wanted to please Jesus at the same moment I was sticking my thumb in His eye by what I was doing.

I have no baseline for determining frequency. This poll is private. I would appreciate it if Catholics would say how often they identify something as a mortal sin in their lives. Really nosy of me, I will agree. And no, I want no details or stories of how you set fire to Uncle Fritz or whatever.


To commit a mortal sin three conditions must be met:
The act or lack of act must be a “grievous” matter.
You have to have full knowledge.
You have to have full consent.
It would appear neither extreme you mentioned is correct. People certainly are able to control themselves knowing a matter is grievous, knowing it is a sin to either act or refuse to act, and doing it without undue external pressure.
Example, I go to the store and give the cashier $10, for a $3.95 purchase, she gives me $16.05 change. Happens everyday, he/she gave you $10 too much; perhaps they thought you gave them a $20 instead of a $10. You realize the cashier made a mistake. Stealing is a grave matter, you understand what you should do, you know it’s stealing if you keep the $10; you also have nothing preventing you from doing the right thing. You do it anyway, reasoning … what ever. You’re not fooling God. Your lack of action (returning the $10) is a mortal sin.
So, not every action or inaction is “sin”. Not every sin is grievous. On the other hand, there are ample opportunities to sin grievously every day.


I’m assuming you mean how hard is it to resist the temptation to sin? I suppose it might be hard for some people… like cheating on a spouse or sex before marriage… I’m not sure what is officially considerred a mortal sin.

But, I’m the kind of person who usually feels guilty all the time, sometimes for silly things, so I know if I do something like have sex before I get married I’d probably never let myself forget it and I’d just ruin myself.

Also, I’m only 15 so the chance to do something really bad doesn’t come up too much. The most I’ve ever had the chance to do is drink or smoke weed or something, and I refuse to touch that stuff anyways.


Well, there are things like masturbation that are very tempting for young people, and they are mortal sins. In fact, once could say that any form of any sin can be mortal, because all sin is grievous, so someone only needs to consent to it and be wary for it to be mortal.


Forgive me; I think you mean “be aware” that it is mortal, yes?



I wish I knew exactly what things are mortal sins and what aren’t. Having only just joined the church, I couldn’t give a frequency for how often, sorry. I need to ask my priest at confession about this really.


Yes, I meant “be aware”. Sorry. Maybe the best way to understand what is mortal sin and what isn’t is by understanding what sin is in the first place.


I put weekly because it occurs at least that often, sometimes daily, sometimes more than once a day, when I was younger almost constantly.

It takes a lot of work and self discipline to avoid Mortal Sin and the near occasions thereof.


When you have questions like this the official answers can be found in the Catechism of the Catholic Church. Rather than cutting and pasting here’s an on-line site:
look up paragraphs 1846 – 1876
Basically, what you said about all sin could be mortal is incorrect. Scripturally we know:
1 John 5:16 He that knoweth his brother to sin a sin which is not to death, let him ask, and life shall be given to him, who sinneth not to death. There is a sin unto death: for that I say not that any man ask. 17 All iniquity is sin. And there is a sin unto death.


In my case, I sin less now than I did before I became Catholic and started going to Confession regularly.

When I first started going to Confession, I didn’t think I could make a good Act of Contrition because I could not honestly promise that I would avoid the near occasion of sin.

I solved that one by resolving that at the time that I say the promise, I really mean it, even though two minutes after I walk out of the Church, there I am listening to gossip - again. :rolleyes:

Learning to walk away, change the subject, say “Hey that’s not true,” etc. took time, and I’m still working on it, but with practice it does get better. These days I can walk into the Confessional knowing that at least I can trust myself to avoid the near occasion of sin if I see it coming, even though I don’t always see it coming and avoid it in time.

To sin mortally one must:

Know that it’s bad (full knowledge), do it anyway (grave matter), on purpose (full consent of the will).


Without God’s grace I can fall into mortal sin. For over 2 months (I think) now I have been free of it. All my sins lately has been venial sins. I often pray daily and try to attend Mass Daily and this strengthen me to overcome sins, especially sin that is grave.

I voted other


Sins are mortal when you know what you are doing is wrong (grave matter, to be specific- and there is no debate on this- these things are part of Church teaching), you are strong enough to resist giving in to it, and you do it anyway. It’s easy to commit a mortal sin, but not something you can accidentally do or do because something is habitual. You should always confess things that involve grave matter because even if they aren’t mortal, you still need to work on avoiding them. Remember though that people aren’t the scum of the earth that some religions teach that we are. We are the children of God, and are made in His image- humanity is inherently good. God is the perfect Father- He watches over us, guides us, strengthens us, and feeds us- He’s not going to let satan take us easily- He will only let us go if we go willingly.

(I’d rather not answer the poll…my sins are between me, God, and my confessor)


This bothers me…I tend to think the Catholics on CAF are conscientuous, pious believers. If you sin mortally every day, but you go to confession only every two weeks, that means most of the time you are in a state of mortal sin. Something seems very wrong with this. I would’ve thought it was a lot harder to fal into mortal sin, and that that would be reflected by it being relatively infrequently. Is it possible scrupulosity should have been part of this poll?


This is something I don’t understand. The above was not meant as an attack and I hope no one takes it that way.


I don’t seem to be having any problem doing it. It is certainly a lot easier than staying on my diet, keeping on an exercise program, keeping the house clean or minding my temper.


I have a major problem wherein I feel as though I am sinning mortally constantly. The things aren’t minor little things, they are certainly grave. What I don’t know is whether or not I am consenting to them. I feel like I must be, like it’s not possible to not consent to these things, but at the same time no matter what I do it happens.

The things I am talking about are looking at women impurely/lusting and having impure thoughts. I know that just seeing am attractive woman isn’t lust, nor is a thought simply going through ones mind unintentionally, but I really am completely lost as to when I consent to them and when I don’t, though I feel as though I do most of the time. It’s a rather miserable existence, but I struggle through it and try to not let it get me down.

This thread is of a great deal of interest to me, because I need to know what I am actually doing. I have asked questions about these things many, many times, here and elsewhere, and never gotten an answer that did me much good.

To me, they are so often clearly mortal sins in my mind, but there is always a huge degree of doubt, too, because I just don’t know when I am consenting; it’s all a blur. It’s almost impossible to walk down the street of my college campus without feeling like I am sinning constantly. But I have this doubt because, in addition to being unsure of if I am consenting, I don’t even know if I am actually committing a sin or if I am just being tempted or even just finding a woman attractive, which I know is perfectly alright and is the way God made it to be, but its so hard to tell when I am doing it the way He intended and when I am sinning. I have tried everything and gotten advice from all sorts of people… nothing’s worked.

I really need to know if these are mortal sins or if I am just doing normal, ok things or being tempted, so I can just move on…


Doing what? I don’t understand your post.


My question is about “full knowledge”. Does full knowledge imply you need to know the consequences? Or is it enough to know that you are breaking a commandment?

I ask because this was brought up in another thread.


I read somewhere that “full knowledge” means that you know what you are doing is wrong. Which brings me to my question in which case I really don’t think I’m doing anything wrong. Being divorced (no annulment), I’ve met someone and have been having relations with her. In so doing, I’m supposed to be committing adultery. But is it truly adultery? My ex-wife is no longer with me - she’s with someone else. How does this constitute adultery. Isn’t the spirit of the law implying that an adulterous act occurs when a spouse has sex with another person without the other spouse knowing (ie. cheating). I am not advocating that swapping is o.k. because both spouses know what’s going on. That’s a different thing and in my view completely sinful. But if I’m in a loving relation with this woman, I’m not sure how this was meant to be an adulterous act. Is my “sin” the same as someone literally cheating on a spouse?

Am I damned to eternity without God because in confession, I don’t ask for forgiveness for this act? I really don’t think it is wrong. I still don’t think God would allow one to live a life of loneliness if it a daily torment to one of God’s children.


I think it is enough simply to know that other people will get mad at you if they find out, or know enough that you would be embarrassed to think that someone knew you were doing it or thinking it. (If you would hide it from your mother or your wife/husband, then you have “sufficient knowledge,” I think.)

I don’t think a person needs to know all the theological nuances - otherwise, only theologians would be capable of mortal sin, and that seems very unlikely, to me. :shrug:

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