I’ve read on this website (catholicapologetics.info/morality/general/venial.htm) that a venial sin could become mortal, but I don’t seem to really understand the concept. Could someone please explain it to me? Thanks.
a) Because of an erroneous conscience or a seriously doubtful conscience concerning the grave malice of a deliberate act. Thus he who erroneously believes that an action which is objectively only venially sinful is a mortal sin would commit a mortal sin if he performed that action. One would also commit a mortal sin in performing an action if he has serious doubts as to whether or not it is a mortal sin or only a venial sin, for one is obliged to solve such a doubt before performing the action.
*This reveals that one loves God so little that he doesn’t care if he is sinning mortally or not. So charity is destroyed.
b) By reason of an end which is gravely evil, as would occur if one performs an act which is a light sin for the purpose of causing another to commit a serious sin.
*Your intent is for God’s honor to be gravely offended, through someone else committing a mortal sin. You love God this little. So charity is destroyed.
c) By reason of the proximate danger of falling into mortal sin if one com*mits a particular venial sin, as would be the case if one were to let himself become angry when he knows that he will very likely end by inflicting grave damage or injury on his neighbour.
*Here, you would care so little about the likelihood of falling into mortal sin that you can’t be said to love God. So charity is destroyed.
d) By reason of the grave scandal which would be occasioned by the com*mission of a light sin, e.g., if a venial sin committed by a priest were to become the occasion of a serious sin on the part of a layman.
*You are so inattentive to your state of being that you lead others into serious sin, which destroys charity in them in a way you could have prevented and were obliged to prevent out of love for them and for God. So charity is destroyed.
e) By formal contempt of a law which binds under light obligation. Con*tempt is called formal if it is directed against authority as such; it is called material if is directed to some other element, such as a disdain for the thing forbidden because one thinks it is of little importance.
*You do something intrinsically venial but you are so spiteful in doing it that it reveals that you hate God. So charity is destroyed.
f) By the accumulation of material which may increase until it is grave matter
*The light matter (like stealing a little money) gets larger and larger to the point where it is no longer light and is a grave matter, which seriously offends God. So charity is destroyed.
No, it is saying if they conclude that there is a reasonable possibility it is a mortal sin, if it is actually a venial sin, committing it is a mortal sin.
This sort of goes along with the idea that the conscience is always to be followed, even if it is wrongly formed.
I want to note very clearly for those out there in the forum that struggle with scruples: do not scruple about this (and I would suggest not reading this thread -but ask your confessor your questions). Obey your regular confessor. A person with scruples can be in a “different boat” than others and needs principles to follow in their case.
Mortal sin is when one has grave matter, full knowledge and deliberate consent. That is basics you need to remember.
Be sure to have a regular confessor to direct you - and give you principles for you to follow. Such is the age old practice in the Church. forums.catholic.com/showpost.php?p=13664714&postcount=3