I humbly admit I am no scholar and may have a deficient understanding of these matters. Is keeping the Sabbath not considered a commandment of Divine law (as far as ommitting the ceremonial customs but retaining a moral law to dedicate ourselves to the Lord), why would it not be considered mortal (with full knowledge) to reject our Saviour on the day he offers himself to us? To reject being in the presence (or partaking of the Eucharist ) of the most precious gift willingly, seems to me that you reject Christ. I would perhaps have the view that one may be less culpable (i.e. not mortal) by being poorly catechised and thus lack the knowldge to the gravity of the situation. In my opinion it would not seem that Canon law is not contradicting Divine law but there is an element of culpability towards it being mortal or venial. Would appreciate your thoughts. God bless.
The command to honor the Sabbath - Saturday, not Sunday - was a temporary prefigurement which pointed, not to a new day of the week, but to Christ Himself. Moral law does postulate the necessity of worshipping God, but how we fulfill that is a matter of conscience. Ideally, we worship Him every day, perpetually, by finding our Sabbath rest in the Sabbath Himself, Jesus Christ. Setting aside a day of the week to meet together and worship is good, but its not divine/natural law. Not attending one Sunday would not be a grave sin, but a heart that lacked any desire to attend at all, could not be said to be in grace and have love for Christ.
