Dear Catholic Exchange:
Hello, I hope you can help me. My husband and I are practicing Catholics and attend mass weekly. However, in a few weeks we will be out of town for the weekend and have been invited to attend my sister's church, which is Lutheran. My niece and my great niece will be participating in the service and I would love to attend.
Would that attendance to a Lutheran Church count as attending church for us, or would we have to confess to missing a week at our church to our local priests?
Dear Friend in Christ,
Attendance at the Lutheran service would not "count" as fulfilling your Sunday obligation. Further, to intentionally miss Sunday Mass is a serious sin for which you would need to go to Confession.
Fortunately, you have not missed Sunday Mass yet. Maybe on the weekend in question you can find a Mass that will work with your schedule. Perhaps a Saturday vigil Mass would do the trick.
It's a good thing that you want to support your relatives, and out of love and respect for them you may attend the Lutheran service. (I'm assuming, though, that your niece and great niece are not fallen away Catholics; you shouldn't go if your attendance would cause scandal or otherwise be misinterpreted as your condoning their leaving the Church.) But be that as it may, the priority must be participating in the Sunday Eucharist.
Since you have a couple of weeks, you might want to read Pope John Paul II's magnificent 1998 apostolic letter Dies Domini ("The Lord's Day"), which beautifully sets forth the significance of Sundays for Catholics. I think you'll find it most edifying. Here's a link:
Here is a link to CUF's Faith Fact on the specific question of missing Sunday Mass: Is Missing Sunday Mass a Mortal Sin.
United in the Faith,
Catholics United for the Faith
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Steubenville, OH 43952