In a recent book on sin and confession, a Catholic writer says that it is a mortal sin to forget to attend Sunday Mass. His argument is that God told the Israelites to “remember to keep holy the Sabbath,” so to forget to make it to Mass must be a grave sin.
We do have a grave obligation to attend Sunday Mass. It’s been Church law since, well, long before any of us were around. The reason is simple: We are creatures, and our first duty is to worship our Creator. More than that, we are social creatures, so it is right that we should worship together, and that worship is done best at Mass, which is the highest prayer of the Church. Since the Church has authority from her Founder, we ought to obey whatever strictures are imposed for our spiritual good, such as the requirement to be at Mass on the Lord’s Day.
So, yes, it is a mortal sin to miss Mass knowingly, but not if one has a sufficient reason (such as illness or the incapacity to get to a church). But the writer is wrong to insist that merely forgetting to go to Mass is a mortal sin. Sin arises only through a deliberate act. This is true of any sin. You cannot commit a sin—either mortal or venial—accidentally.
During one three-day holiday, I remember waking up on Saturday (already having had Friday off) and thinking, for a moment, that it was Sunday and that I had to hurry to get ready for Mass. Friday had been my Saturday, my do-nothing day (not that I really do nothing on it, but you know what I mean), and the day after my do-nothing day always starts with Mass, so . . .
If that kind of mistake is possible (even common, I think), so it is possible to err at the other end of the weekend. Imagine the case of a person who normally has Saturday and Sunday off but this week had to work on Saturday. He might wake up on Sunday and engage in his routines as though it were Saturday, realizing too late in the day that he missed Sunday Mass.
Did he commit a mortal sin by forgetting to attend Mass? No, since he did not intend to miss Mass. Without consent, there is no sin. Mortal sin requires three elements: serious matter, knowledge of the sinfulness of the act, and free consent. If any one of these is omitted, no mortal sin is committed.
So, the book is wrong to say that forgetting to attend Mass (not faux-forgetting, which is used by some as an excuse for idleness, but actual forgetting) is a mortal sin. Unfortunately, some readers of the book, particularly those with a tendency toward scrupulosity, will not see through the error, which is made by a well-respected writer, and may be led to see sin where there is no sin.
The lesson: Those of us who write need to write carefully, and those of us who read need to read with a critical eye. After all, even Homer nods.