Lying to parents about “unimportant” subjects


Firstly, I would like to say that even though this may seem dumb or unnecessary, it has REALLY made me preoccupied.
It all started yesterday evening, when I was using my cellphone to search if something I had done was a sin. Then, my mom (who I’m really intimate, as we live, just the two of us, together since I was born), asked me what I was doing. But as I didn’t want her to know of the search, I opened another app and told I was using it… Later on, I didn’t tell her about the search I was doing, because I really didn’t want her to discover the “sin”, which I recently found out it wasn’t even venial…

My main concern is if because it was my mother, it’s gravity is increased…

My question is: was this lie a mortal sin, or as I simply didn’t want her to find out about a “sin”, it’s gravity is reduced to the point of being venial?

Sorry for the English (I’m Brazilian)…


I’m not diagnosed as scrupulous, but I do tend to “over think” the subject…


St. Thomas Aquinas says that lying is mortal in three cases:

  1. The lie is about something long lasting and important such as lying about religion or science. However if the lie causes no change in how the person acts or perceives the world its not mortal.

  2. You lie specifically to hurt someone. I.e. someone’s reputation

  3. You lie publicly to avoid getting in trouble.

I’ve significantly abridged the Saint’s words and suggest you read it for yourself:

Edit: I see you’re not a native English speaker. That will make reading the text very difficult for you probably. Perhaps google “St. Thomas Aquinas on lying” in Portuguese and see if you can’t find a translation more suitable for you.


When you go to Confession your sins are private. It seems to me that you were seeing if you needed to go to Confession? That would be a private matter, you don’t have to tell your sins to anyone but the priest.


Every sin is a lie, however, the culpability can range from venial to mortal.


Sounds like a great question for your priest. :slightly_smiling_face:


Thank you all for your answers! You really helped me a lot!


I think your issue is more about boundaries and communication than about lying. You may need to know how to deflect your mother’s questions in other ways. For instance, by using humor. Say something like, “It’s top secret. I’m working with the FBI on this one.” Or you could just say, “It’s just a small search for something of personal interest.” Or you could re-direct your mother’s attention. “What are you going to do after I’m done this google search, Mom?”

Basically, always remain kind, but keep some distance.


Thank you all for you answers!
I actually told my mom about what happened and she helped me to realize it was only venial. She said she already knew I wasn’t telling the complete truth… Anyway, I’m at peace now…
Thank you all!


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