Is it mortal sin?

I just learned that anything sexual activities done unmarried is mortal sin in the eyes of god. and to become mortal it has to comply with 3 rules: Grave, knwoledge, free will to become mortal.
At the time I had oral sex with my girlfriend, I knew it was a sin, but didnt know this act is MORTAL SIN. Didnt even know the difference between mortal and a regular sin. So, was it mortal or venial sin what I did?

For example: if someone steal a car, of course he knows stealing is critical and wrong and of course everyone knows everything done bad is sinful, but the person doesnt know that stealing is a mortal sin, and he just saw it as anyother sin. Was stealing the car venial because he didnt know what mortal sin is??

Go to confession and make a firm commitment not to do this any more. ]

You can confess both mortal AND venial sins in confession. Since you knew it was a sin and did it anyway, I suggest you confess it.

As previously noted you can and should confess both mortal and venial sins although you are only obligated to confess mortal sin. So I would recommend you confess the sin if there is any doubt whether the sin was mortal or venial.
Here is what the catechism says;

#857 For a sin to be mortal, three conditions must together be met: “Mortal sin is sin whose object is grave matter and which is also committed with full knowledge and deliberate consent.”

I think the key word here is “Full” it does not say you must have “Full” knowledge of the gravity of the sin but only “Full” knowledge that the act is a sin. Since this meets the other 2 criteria for a mortal sin I would argue that you did commit a mortal sin but I would recommend you talk to your confessor or parish priest.

Thank you very much.

I will confess and will not do it again.

I thought for it to be a mortal sin, you had to meet all 3 requirements. Not just two of them? :confused: I was always told in cathecism that it was a solid requirement that a person had to have full knowledge that something was indeed a mortal sin. Just having a vague idea something is kinda wrong makes it more of a venial sin.

It’s not really

**
I. Deadly Mortal SIn
II.Mortal Sin
III. Regular Sin
VI. Venial SIn**

It’s more

I. Mortal Sin
II.Venial Sin

It goes into different degree’s though. I do believe that oral sex is one of the 5 sex sins is it not? So in that case, it’s a bit more serious than, lets say, you had sex with her the ‘normal’ way. Its a mortal sin if you know it is bad, and do it anyway with your free will.

It seems to me that you did not have full knowledge of this sin, but go to confession anyways, because if it’s not a mortal sin then it’s definitely borderline. Remember that mortal sin produces a deep separation from our Lord, sometimes even to the extent that we become unrecognizable to him at death.

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