Mortal sin by thought


I believe there is such a thing as mortal sin by thought even without action. The obvious example is lustful thoughts. When exactly do such sinful thoughts become mortal?

A) You think of these thoughts, understand that it’s wrong and yet continue dwelling on them
B) You mindlessly think of these thoughts for a few seconds, then realize what you are doing and immediately try to dismiss these thoughts

A to me is mortal but B feels like it’s venial as your “consent” is questionable. Is this true?


this seems like a topic designed to get scrupulous people to spaz out about intrusive thoughts.


For sure I can be scrupulous but just genuinely curious to see what others think.


Sometimes it’s good to think less and accept what the Church teaches us. That takes the onerous burden of justice off of you and leads you to simple trust.

Mortal sin must have the cooperation of your will. Thoughts (or “temptations”) are not acts of your will.
If you move yourself intentionally to entertain, then you can evaluate that.

Generally speaking: morality evaluates human acts, not temptations or random thoughts.
Generally speaking: if you doubt the mortality of a sin, it is not mortal. I have always heard this from good priests in this regard.

Be at peace. Trust in the Lord. Meditate on psalm 103.


I’ve been scrupulous in the past. Curiosity is not an aid in this regard. Or “curiositas” as it is described in classical theological discussion.
Inquisitiveness seeks genuine answers to relevant questions. Curiositas seeks knowledge that is superfluous, or not germane to one’s competence or state in life. Or knowledge that is actually destructive to one’s peace of mind.

Do not pry into things that are beyond your understanding and competence. They lead to speculation that will drive you to distraction. Leave it to God.
Do your best.
Psalm 103.
St Terese the Little Flower.
Trust. Concern yourself with those things withing your scope.

call your mom, visit a nursing home.


I’ve talked about this in a few other threads, so let’s try here. My immediate cause was reading “Nine Essential Things I’ve Learned About Life” by Rabbi Harold Kushner. I’ve read five of his books, and I find him filled with common sense. However, in this book he says–and elaborates on–the idea that a sin MUST be an action, not a thought. To me this is nonsense.

Example: You see the movie “Old Man with a Gun” where Robert Redford robs banks. You say to yourself, “That looks like fun!” and then go have dinner. Not a sin. A passing thought.

But…what if you see the movie and say to yourself, “I could rob banks too!” and you begin a month-long immersion in the planning of a bank robbery. You buy a gun, find out where the guards are stationed, where the alarm bells are, what time of day there are the fewest people, what happened the last time they were robbed, and on and on. You are obsessed with robbing this bank. First, to get this out of the way, no, the police are not going to arrest you. It’s not a crime to think about robbing a bank, or (as far as I know) to plan to rob a bank. But is it a sin? Of course, and probably a mortal one–after all, you are planning something involving a lot of money, people could get hurt, etc.–it’s a big deal. And you give your full consent. And it’s clearly a bad thing.


This isn’t true, no thought is ever mortal. I used to confess my sins for the past 3 years and they were all venial and my priests would tell me they were forgiven at mass, and when I take communion. So, there is no such thing as thoughts being mortal sins. They’re all venial sins, since you didn’t commit any offenses with actions or deeds. You can say the I confess to you for venial sins, every thought word and venial action will be confessed by you out loud in Mass, or at home even


Personally i believe no thought is ever a sin. Thought police anyone? If you are kind and generous in your actions and words, this is what matters in life.

However, dwelling on hateful or fearful thoughts can be bad for your physical and mental health, so always good to share your feelings with those you trust and who love you.


Temptations aren’t sins in and of themselves because even Jesus was tempted and He did not sin!

“Then Jesus was led by the Spirit into the wilderness to be tempted by the devil. After fasting forty days and forty nights, he was hungry. The tempter came to him and said, “If you are the Son of God, tell these stones to become bread.””- Matthew 4:1-3

Intentionally enjoying these thoughts is sin


I strongly disagree. How miserable would one’s life be if you had to maintain G-rated thoughts your whole life. What about when reading a novel or playing a role playing game? Your mind is your own world when you can literally think and use your imagination to do or be anything you wish. What matters is your words and actions in real life your thoughts are your own and yours alone.


When you said how miserable it would be to have G rated thoughts your whole life, think about this, Theresa of Avila said there are few souls on Earth that wouldn’t even want to commit the least venial sins. This is a holy, a saint goal to have as Catholics. We should all be striving not to sin with even the smallest venial sins ever


I suffered from scrupulosity alot. My personal understanding is that you are generally correct. The only thing I’d say is that B might not be a sin at all. You can’t, as far as I know, mindlessly commit a sin of commission.

No one has 100% control of the thoughts that pop into their head.


As mentioned earlier one’s thoughts and Imagination should never be limited. And one’s own personal thoughts are not sins. Only actions and words matter


Just thoughts are not sins, but its called a temptation,the occasion of sin,but if we keep lingering on lustful thoughts, when given heed to such things, can lead you to further sins, willfully and end up in self abuse which is a mortal sin.

Sirach 37:18 The mind is the root of all conduct; it sprouts four branches good and evil, life and death;and it is the tongue that continually rules them.

James 1:13 No one, when tempted, should say, “I am being tempted by God”; for God cannot be tempted by evil and he himself tempts no one. 14 But one is tempted by one’s own desire, being lured and enticed by it; 15 then, when that desire has conceived, it gives birth to sin, and that sin, when it is fully grown, gives birth to death. 16 Do not be deceived, my beloved.


Lustful thoughts can lead to lustful actions or at the VERY LEAST they sexually excite us and this excitement is suppose to be saved for marriage.

What you think about influences what you do, ideas are powerful. Therefore we must guard our thoughts.

I’ve seen studies that show most serial killers are addicted to porn, masturbation, and think about sex and rape all the time. Clearly their thoughts caused them to sin mortally. Therefore, we can’t endulge these thoughts.

As I said earlier, the thought itself isn’t a sin, Jesus was tempted by the devil. But giving into these thoughts and enjoying them is a perversion of morality


That is definitely false equivalency as I can guarantee you that 99% of teenagers are thinking about sex 99% of the time.

So the thought itself is not sinful


I just said the thought itself is not sinful. We can’t control how our mind wanders but intentionally staying on the thought for 5 minutes and enjoying it is wrong.

Logic: masturbation is wrong, imagining naked women tempts you to masturbate, therefore it is wrong.

“If anyone causes one of these little ones—those who believe in me—to stumble, it would be better for them if a large millstone were hung around their neck and they were thrown into the sea.” - Mark 9:42

Jesus is very clear here that anything that causes you to sin is a sin. Just because lots of people have impure thoughts doesn’t mean the thoughts are good. They are called impure for a reason. Yes we have the thoughts but that doesn’t mean we should dwell on them.

This logic would say it’s fine for people to think about rape because hey, they aren’t actually raping anyone…


Matt 5:27-28 - “You have heard that it was said, ‘You shall not commit adultery. But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart."

Feels to me like this is definitely referring to thoughts and Jesus clearly condemns such thoughts. This would be a case of “A” as I mentioned above.


Whoa, lots if contradictory ideas here. so the thoughts are impure but are not sins in your opinion? What about the person that is obviously thinking about sex all the time but does not masturbate? I think imagination is not limited or Bound by rules and should never be. So yes even thinking about murder rape pillaging, Dungeons & Dragons, whatever, is not a sin at all but your own thoughts. The exact same reasoning for reading books or watching Rated R movies. They’re not real.

But going back to sexual thoughts it’s quite a long stretch and not very fair to always associate sexual thoughts or masturbation with criminal sexual assault.


What he means is that there are times were thoughts can fly into your head without provocation or approval. So long as you don’t entertain them, they’re not sinful, even if the thought contains sinful activity or ideas.

I’m assuming here this person allows him/herself to think lustful thoughts and wants to do so. That would be sinful.

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