A reader writes:
I have a baptized daughter who is a few months old. My wife and I went home to my parents this weekend. They went to Church Saturday night as we were visiting other relatives. On Sunday morning my mom offered to watch our daughter while we went to Church. I agreed.
On the way to church I began to wonder if not brining my daughter to church was a sin. Was it? And how grave was it? I abstained from communion because I wasn’t sure.
I’m not clear from your answer whether you took your daughter to Mass Saturday or if it was just Sunday morning when you didn’t take her to Mass. Either way, it doesn’t matter, because a child that young is not required to attend Mass. The Code of Canon Law provides:
Can. 11 Merely
ecclesiastical laws bind those who have been baptized in the Catholic Church or
received into it, possess the efficient use of reason, and, unless the law
expressly provides otherwise, have completed seven years of age.
The law regarding who has to go to Mass on Sunday (or Saturday evening; either satisfies the Sunday obligation) does not specify an age. It simply says:
Can. 1247 On Sundays and other holy days of
obligation, the faithful are obliged to participate in the Mass.Moreover, they are to abstain from those works and
affairs which hinder the worship to be rendered to God, the joy proper to the
Lord’s day, or the suitable relaxation of mind and body.
Since there is no specification of age here, canon 11 means that children under 7 years of age (or people who lack the use of reason or people who are not baptized) are not bound to attend Mass.
It thus was not a sin to leave your daughter in the care of your mother.
Parents do have a moral obligation to ensure that as their children age, they get in the habit of going to Mass so that once the obligation kicks in at 7 years of age they’re used to it, but this is not an obligation that means they have to be there every single Sunday, and it certainly does not mean that children less than a year old have to be taken to Mass. Children that young are incapable of forming the habit of going to Mass.