Is lying to parents mortal sin?

I promised my dad that I would enjoy 2 hours of relaxing and then I would study. But I went over the 2 hours and while I knew it, I still continued relaxing anyway.

Is this a mortal sin? I mean deliberate consent is there, but I think it is a venial sin so I thought it would be okay if I make it up with a penance after. Did I commit a mortal sin?

Offer a few reasons why you think it would be a mortal sin and a few reasons why you think it wouldn’t be, and we can go from there.

If you learn how to discern these things for yourself, you won’t have to ask random people on the internet. :thumbsup:

In any event, we should make an act of contrition before we consider how grave a sin was. Concentrating too much on the act itself can distract one from ever being truly sorry for it. There was an apostle who did this…

Mortal sin:

  • Disobeying the 4th Commandment
  • Failing to keep a promise
  • Noticed that I wasn’t keeping it but deliberately did so anyway

Venial sin:

  • While I am disobeying it, it is not grave matter (I think) and it does not do much harm
  • I intended to keep the promise at first, but failed to do so after. So no intention to lie.
  • I thought it wasn’t grave matter. So deliberately did it, but still venial sin
  • I had intentions of making penance for that sin, but I still wanted to continue relaxing first and make it up for another day (which I think is venial matter still)

What do you think?

You still have to explain why you think any of these criteria are/could be objectively grave matter.

Many Catholics are under the mistaken impression that any violation of any commandment is automatically grave matter.

Many Catholics believe wrongly that all promises bind under pain of mortal sin.

Many Catholics believe incorrectly that deliberate action is automatically grave matter.

  1. I used to be over that, however I read in a Catechism book yesterday that if someone doesn’t know whether something is grave matter or not and just goes ahead and does it anyway, it IS mortal sin.

  2. Promises are not always mortal sin I understand. However, I was unsure as in relation to the 4th commandment I was not that certain whether lying to a parent would be considered dishonoring them, but at the same time I had the thought of ‘‘nah it can’t be grave’’

  3. I’m aware of deliberate venial sins. In my case, I thought that my case was deliberate so long as I do not keep repeating this over and over again.

But yeah, you’re right on most of the parts, I’m still uncertain when it comes to matters like these. When does violating a commandment become mortal sin? Is it only sins against charity, justice etc?

This may be of interest to you.

In your case, I wouldn’t say it’s a mortal sin. Lying to parents can be a grave matter, depending on the nature of the lie, i.e. you lie to your parents about your financial status to get money from them.

I am not God, just a random poster on the internet.

But from where I sit, the very fact that you are asking this question indicates a lack of self knowledge and a developing state of maturity that affects your culpability.

Please do not be offended by that, it is just an observation that we must all make about ourselves. So the task is not to use immaturity and lack of self knowledge as a presumptive excuse, but as a launching point to grow.

Presumptive means that you do something with the pre-formed conclusion that God will forgive you. It seems to me that presumption is a more serious issue than this particular violation of the 4th commandment.
Maybe you can simply “own” your failings, go to confession and move on to bigger things.

I think you need some counseling from your priest on how to form your conscience because this is way out there.

*'Let us now proceed. We have spoken of the examination regarding mortal and venial sins. But were a person to do an action with a doubt whether it was a mortal or a venial sin, what kind of sin would he commit?

He would be guilty of mortal sin, because he exposes himself to the danger of grievously offending God. Hence, before he acts he must lay aside the doubt; and if he has not hitherto done so, he must confess it…But the scrupulous, who have doubts about everything, must follow another rule: they must obey their confessor. When he tells them to conquer their doubts, and to act against scruples, they should obey with exactness; otherwise they will render themselves unable and unfit to perform any spiritual exercise.’ *
St. Alphonsus Maria de Liguori

You need to bring all of your theologically moral questions to your regular confessor, since we may make it worse

Actually, for a real scroop, that is a temptation in itself. Poor Father.

The only thing you’ve noted that could “rise to the occasion” is what I bolded. Mortal sins are always “contrary to” a Commandment, inasmuch as each Commandment is a precept of CHARITY.

If it is not gravely uncharitable - toward God or another - then it is not mortal sin.

  1. This is not the whole story. Consider this - did you stop to make sure that reading this post was not mortal sin? NO? Well… Don’t worry, you didn’t commit a mortal sin for not being sure it wasn’t. That is because there was not sufficient doubt cast on the matter. If you deliberate sufficiently and arrive at a real conclusion that “this might be a mortal sin” and decide to do it anyway in freedom (and not in some situation where the conscience is perplexed in such a way that every possible option appears to be gravely wrong, in which case you must follow the most probable opinion, or “make your best guess” based on what influences you, like your first reaction, whether there is a civil law, whether you received counsel to act a certain way, etc.), in the act of consent there is a grave lack of charity implicit due to your disdain for following the law. Surely, this is not what happened. Maybe you had a passing “feeling” that “this is wrong, maybe it’s a ‘mortal sin,’” but that does not suffice for what St. Alphonsus is talking about.

  2. Failure to keep a promise illegitimately is not lying. Lies occur at the time of their telling. We must make as many distinctions as we possibly can when discussing moral questions… (and anything else in theology!)

  3. A deliberate venial sin actually involves two sins… The sin itself, and the deliberate consent to it. Ouch. We should move away from these real quick!

  1. How do I differentiate between this? Before going on with the sin, I researched a few articles first on whether breaking a promise was a mortal sin. I was quite convinced that it wasn’t as I just wanted to commit a deliberate venial sin and not a mortal sin. But I still had some doubts on whether breaking the 4th commandment alone was a mortal sin. Does that count for St. Alphonsus description?

  2. Yeah, I gotta work on this :confused: to me I always have the idea that ‘‘ah as long as I don’t commit mortal sin I’ll be fine right?’’

I hate when people say this without qualifying it; it does not apply to the scrupulous. Rather the opposite does. Scrupulous people are, AFAIK, generally supposed to assume that if they are genuinely not sure if it is grave matter, that it was not. But they are also supposed to have a regular confessor to discuss things with and help them recover.

My situation was like this: I wanted to continue relaxing and start studying the next day, however I was fully aware that I was being lazy but I assumed it was a venial sin though I had some doubts about it being a mortal sin. But I was more convinced that it was venial, so I committed to the act of continuing relaxing anyway. Would this be considered a mortal sin?

Ask your confessor.
Have you done that?

Listen to your confessor.

Honor thy father and mother.


Yes I would say that you need to go to confession about this.

  1. Okay. Let’s recognize the irony of doing intellectual work to make sure what you are doing by not doing intellectual work isn’t mortal sin but is only venial sin.

And no, it does not, if I understand you correctly… Saying you “had some doubts on whether breaking the 4th commandment alone was a mortal sin” is a very confusing clause to me… Breaking the 4th commandment in the action you were about to commit? How can you have doubts when you were also “quite convinced that it wasn’t”? See where I am confused?

  1. Yes. Eliminate this immediately.

No. It does not appear so.

But mention all this in confession anyway. It’s good for you. :thumbsup:

After reading several of these threads, I’ve come to the conclusion that saying anything other than “talk to your priest” is a disservice, as it just adds layer upon layer of variables that add to the mistrust.

Okay, I’m planning on going tomorrow evening anyway

Ah so it is not a mortal sin :slight_smile: thank you, certainly removed some of my anxiety and stress. Either way, I’m confessing this tomorrow in confession and gonna do my best from now on to avoid these deliberate venial sins.

DISCLAIMER: The views and opinions expressed in these forums do not necessarily reflect those of Catholic Answers. For official apologetics resources please visit