A recent friendly discussion of differences between the Eastern and Western lungs of the Church caused me to conclude that the modern Western Church struggles with laws and rules in a way that the East doesn't, and perhaps a way that the West didn't used to. The predominant dichotomous groups within the Church today (e.g., conservative and progressive, traditional and charismatic) seem to be divided over rules: are they supremely important, or of little importance whatsoever?
So, too, does it seem to be very easy for a person striving for holiness (especially one with a duty-bound conscience like my own) to see fault everywhere, and to get caught up in the rules (Commandments) and the "supposed to"s and the "could have been better"s... Admittedly, humility does require that one see one's own faults, but it absolutely does not ask one to be overly anxious about them. Thus the problem: scrupulosity.
Fortunately, Our Lord has blessed me with a liberal trust in His loving mercy, so I am usually quick to accept His forgiveness for the little things I screw up on all the time. But how does one tell conclusively that a sin is venial as opposed to mortal? Oughtn't one to refrain from receiving Communion if ever in doubt, so as not to profane such an august Sacrament, even unintentionally?
Two responses spring to mind. First requires me to define a mortal sin: a sin that cuts you off from God in such a way that you are incapable of receving His graces until you repent and receive His forgiveness through his sacred minister, the priest. Three conditions must be present in order for a sin to be mortal: Grave matter, full knowledge, and deliberate consent (cf. CCC 1857). Or, as they taught us in middle school, it must be seriously wrong, you have to know that it's seriously wrong, and you have to freely choose to do it anyway. In short, a mortal sin is like choosing to spit in God's face and then turning your back on Him. But many Catholics often get caught up in that first condition, grave matter, and count themselves (or others) to be in mortal sin when mitigating factors such as poor education or addiction reduce one's culpability for that sin. In other words: Many good people who are striving for sanctity misdiagnose venial sins as mortal sins.
The second thing that comes to mind is a particularly memorable paragraph I read a few years ago from the Diary of St Faustina, a poor, sparsely educated Polish nun who was blessed with mystical visions of Our Lord on a regular basis (the words of Christ are in bold):
(156) + Once, I desired very much to receive Holy Communion, but I had a certain doubt, and I did not go. I suffered greatly because of this. It seemed to me that my heart would burst from the pain. When I set about my work, my heart full of bitterness, Jesus suddenly stood by me and said, My daughter, do not omit Holy Communion unless you know well that your fall was serious; apart from this, no doubt must stop you from uniting yourself with Me in the mystery of My love. Your minor faults will disappear in My love like a piece of straw thrown into a great furnace. Know that you grieve Me much when you fail to receive Me in Holy Communion.I don't mean to suggest that I know what anyone else should do with their interior life, but that paragraph did it for me. I told Our Lord that I would no longer fret over whether to receive Communion, but would go unless I know I was fully guilty of a grave fault, which is rare, because His Spirit is with me.
I still go to Confession regularly. Like every other human being (with two exceptions), I sin. But I don't let my sins get in the way of my relationship with Our Lord. I simply apologize, accept His generous, unconditional forgiveness, and move on with my life and His plans for it. It's a beautiful relationship we have, and I look forward to Him continuing to transform me in His love.