How do you know you've committed a mortal sin?

Ok, I understand the 3 requirements of grave matter, full consent, and full knowledge, but in practice, this is not terribly helpful.

I am scrupulous, but even if I wasn’t, I’d still be none the wiser about many of the sins I commit, and whether or not they are mortal sins.

I heard St Alphonsus said to scrupulous folks, to give yourself the benefit of the doubt, but I find this conflicts with the idea of not receiving Holy Communion in a state of mortal sin, and if you are unsure of your soul state, then you commit a mortal sin since you show yourself prepared to commit evil (receiving Holy Communion unworthily) just as quickly as good.

I am not a happy camper, as tomorrow, the First Friday, I was hoping to go to Mass and receive Holy Communion. Now I am not sure I can.


A priest once told me that if you are in doubt as to whether or not you committed a mortal sin, chances are pretty high that you didn’t. But if you know that your sin was grave in nature then you probably should go to confession. I’m a bit on the scrupulous side so I always want to be safe. But remember that God’s mercy infinitely exceeds your sins and He is in your court. You do not want to presume the condition of your soul but you don’t want to live in despair either…teachccd

How would I know if my sin was grave in nature?

The sin I committed, was one of thought, the desire to look, then looking. I looked. But I tried to restrain myself. My thoughts didn’t fall into the gutter, so to speak. I was tempted to look, I looked away, but then I looked back, then away, then back again. Like I say, my thoughts didn’t go bad, so to speak. In my defence, there is a strong force of habit to this matter, and also some deep-seated emotional wounds which are two of the main factors in this. At the time, my will towards God was good, yet I knew I shouldn’t look - I tried not to, but in the end I did.

I am not making excuses for myself of course.

I just am really struggling with this. Only on Monday I was at Confession and my priest said to make a monthly confession, rather than the weekly one I had been making up to that point.

To me it sounds like you were resisting temptation. You just had to try a few times. If you didn’t have thoughts of lust (ie. thinking of what you might want to do with that person) and you continued to resist, then you probably are o.k… Only you know how far you let your thoughts go but by what you described it seems that you were not lusting after that person.

I am assuming that you are a guy (didn’t check your profile) and if you are these kinds of temptations occurr pretty regularly. Probably for women also, but since I am a guy I cannot speak for them. For me when this happens, I continue to ask for strength and like yourself I always think of God and how I am offending Him if I continue. I do confess this but I do not consider them mortal sins. There have been times when I knew that they were and it’s pretty obvious to myself when that happens.

Always listen to your confessor but if you are really thinking that you are in mortal sin you should take the side of caution and get to confession. It’s better to refrain from the Eucharist one time than to receive if you are in mortal sin. But, in my honest and humble opinion, I do not see mortal sin in the event that you described. Maybe other posters will disagree and that would be why a confessor is more to your advantage than this forum. Next time you go explain to him exactly what you wrote here and then you will know from then on…peace…teachccd

Thanks. Your advice has been helpful, yet I am still not sure. :o

My intention, in my desire to look, was not good, even if I did struggle with the looking.

I know. I am with you on this one. Your struggle reminds me of when St. Paul states in 2 Corinthians 12 that when “I am weak, I am strong.” Maybe a little story and then I’ll let others chime in:

Two monks were taking a walk in the woods when they came across a scantily clad woman who was having great difficulty crossing the stream. So one of the monks picked her up and carried her across the stream. After a considerable amount of time the one monk asked," How could you have picked up that half naked woman and carry her?" To that the second monk replied, “After I crossed the stream, I put her down. You, on the other hand, are still carrying her”.

Anyway, there is not a cut and dry answer to what constitutes mortal sin. Only you and God know with the help of your confessor. If your intention was a full consent to reject God and replace Him with an infinitely lesser pleasure then you sinned mortally. How far did you go? Only you and God ultimately know. But (and I stress this) follow the advice of a good confessor. A good priest can pick up on any scrupulocity and guide you to a healthier relationship with a God whose essence is love.

I hope that this helps. It’s about all I can say from where I stand. May God bless you and keep me in your prayers as I will you…teachccd :slight_smile:

Have a look at this guide.

In the Sermon on the Mount. Christ taught that Lust comes from within mans Heart not from without. We all know what is in our Hearts and God knows as well. We know when we have commited a mortal sin because it bothers our Consience without a dought. You did not say what you were looking at. Was it a Person or a Movie or a bad picture? What were your thoughts wnen you were fighting this temptation? Only you know that.
.However since the Priest advised you to go to Confession once a Month instead of once a week you are living a good life.


It seems to me that whenever I have moved my heart ( and felt it) in defiance to the good counsel of my conscience and the Church teachings, it is always a mortal sin. Somehow, this death of grace in my heart is really felt like a result of violence in there. After that you don’t feel like looking at Jesus in the eyes except with a bent head. Well, there is always that thing which has been spoken of from the beginning: SHAME and NUDITY (the feeling that your ‘secret’ intention and action is seen fully by God)

I can identify with what you have written.

What is so insidious about scruples is that real sin can appear to me as scruples and vice versa. The devil uses my scruples against me to inspire despair and make me sin more by inciting rebellion in my heart against God.

What scares me is how easily I forsake the Lord and choose sin, pride, rebellion etc…

Go to a good priest for spiritual direction. Tell him about your situation. If he judges you to be scrupulous, don’t let your scrupulosity serve further to ruin your communions. If you can go by what St. Alphonsus says because you are truly scrupulous, then follow through with his direction - like a brave Christian soul. Your priest will know how to counsel you if you are scrupulous. But if he doesn’t know much about it, seek out another priest.

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