From a reader…
After a valid confession, if we later remember a forgotten mortal sin, are we strictly obligated to mention it in our next confession, or is it optional? I have found contradictory answers by both priests and laypeople online. Some say you CAN, but it’s not required. Some say you MUST, otherwise it’s a mortal sin and amounts to the same thing as concealing it. So which is it?
First, let’s be clear about something.
If you honestly forgot, or didn’t remember something, but you did your best at the time of the confession, then all your mortal sins are forgiven, even those which were forgotten or not remembered at the time. However, if you deliberately exclude confessing a mortal sin that you do know about at the time, the absolution is not effective and you have compounded your deliberate omission with the sin of sacrilege, which must now also be confessed.
MUST we confess sins which we had forgotten? After all, they’ve been forgiven already, right?
Let’s start with a couple of quotes.
“All mortal sins of which penitents after a diligent self-examination are conscious must be recounted by them in confession…”
You have not yet “recounted” all mortal sins. Your next confession is your chance to do that.
And 1983 Code of Canon Law 988 §1:
“A member of the Christian faithful is obliged to confess in kind and in number all grave sins committed after baptism and not yet directly remitted through the keys of the Church nor acknowledged in individual confession, of which one is conscious after diligent examination of conscience.”
The key word here is “directly”.
Sins that are confessed have been absolved directly. Forgotten sins have been forgiven indirectly.
You have not yet had those forgotten or newly remembered sins forgiven directly.
Hence you are obliged to confess them too.
Bottom line, yes, you are obliged to confess those newly remembered mortal sins, in kind and number.
However… remember that remembering the sin does not put you back into the state of mortal sin again by the fact of remembering it.
Even if you have just walked out of church after having made your confession to the best of your ability and – BAM! – you remember something – you are not strictly obliged to turn around and go back into the church and start over. You can but you need not at that very moment. You should confess those remembered sins in a future confession, which should be regular and/or as frequent as needed.
It really helps to make a daily examination of conscience and make that examen a part of your routine, such that over a period of time, you don’t have these lapses very often or at all. Some people have better memories than others. However, that examination can really help you be thorough and, this is important, far more self-aware. “Know thyself!”, the ancients cried! Perhaps one of the wisest bits of advice ever given.
GO TO CONFESSION!