I am glad the OP started this thread. I think it is an excellent topic of discussion.
Hi, no I believe that Catholics are not permitted to worship in a Protestant church, if you HAVE to visit a Protestant church, then merely observe… don’t participate actively. It would be better not to sing, etc, as that is not passive but active participation. Here’s an article explaining this:
christendom-awake.org/pages/thomas-crean/praying-with-non-catholics.htm
God bless
I read part of the article and skimmed the rest (sorry, I’m a slow but impatient reader

) but I did notice a few things. There were some quotes about how bad it is to hang with heretics, but I saw a couple references that it is not against church law. It also mentions JPII who, from what I can tell, was big on interreligious dialog, and even kissed the Quran. Of course, many Catholics who are 100% in line with the papacy said he was wrong to do this.
If I am wrong about any of the above, or have mischaracterized the article or JPII, please correct me.
Now for my personal opinion:
I think we need more interreligious dialog, and I see nothing wrong with singing praise with Protestants. I do see something wrong with going to a Protestant church and sitting there conspicuously silent.
Honestly, I have little patience these days to read a lengthy, scholarly argument, and when I do, I usually don’t understand half of it anyways, especially when they use words with five or more syllables.

These things are necessary and good, I suppose, but let’s get back to basics, and to the Bible and see what St. Paul has to say in this passage which I think applies:
1 Cor 9:19-23
19 Although I am free in regard to all, I have made myself a slave to all so as to win over as many as possible.
20 To the Jews I became like a Jew to win over Jews; to those under the law I became like one under the law—though I myself am not under the law—to win over those under the law.
21 To those outside the law I became like one outside the law—though I am not outside God’s law but within the law of Christ—to win over those outside the law.
22 To the weak I became weak, to win over the weak. I have become all things to all, to save at least some.
23 All this I do for the sake of the gospel, so that I too may have a share in it.
The same chapter has other good information about exercising one’s conscience if invited over by someone with different beliefs, and IMO it gives support to my position. In fact, that’s where I got the idea in the first place, and why I am not afraid to speak of it. If I am wrong, then so is 1 Cor 9.
Personally, I have been influenced quite a bit by contemplative teachers, who suggest there is a kind of spiritual unity among all human beings, that hasn’t been realized yet. Truth is Truth, and each religion at least attempts to discover it from its own point of view. So we’re all seeking the same God, although we disagree on the particulars.
Remember that St. Paul did not have the benefit of scholarly journals; and I’ve heard that most of his letters were actually written before the gospels were, but don’t take my word on that. The point is, the early believers evangelized by their lifestyle and by word of mouth, not by complicated essays breaking down a simple issue into a gazillion pieces.
Either way, I think Jesus makes it clear that kindness and mercy toward other people trumps doctrine and even adherence to that doctrine. (the Good Samaritan, picking grain on the sabbath or washing of cups – the “whitewashed tombs” passage, the Pharisee and the tax collector, the faithful woman he called a “dog” to name a few examples)
Besides, if we really think that the Protestants are misguided and might even go to hell for their disagreements with Catholics, what better way to gain their trust by showing them a little respect. Fishers of men need to first go to where the fish are, and then use convincing bait. Sitting there, silent, with your arms crossed, is not a formula to gain respect. And if you don’t have their respect, you can forget about telling them anything about our own faith. There is nothing wrong with staying inside the Church and never straying into “enemy” territory, but if you do that, don’t complain about the existence of people you refuse to associate with, because you’re not doing anything to help the situation.
In Wichita, the Catholic diocese operates
two “Lord’s Diners” that are located in poor areas of the city and feed a hot dinner to hundreds of people a day, 365 days a year, no questions asked. Not like a government program where you have to prove that you fit the right criteria, not to mention paperwork, red tape, and waste – and let’s not forget the political wrangling over these programs. No. At the Lord’s Diner, volunteers and donors are from many different religions, and even some non-religious. Large corporations with no religious affiliation donate food and money. Why is it we can stand hand in hand to help the poor, and accept Protestant time, talent, and treasure, to advance our projects … but we can’t sing a song of praise together? That makes zero sense to me. :whacky:
To an honest question, that is my honest answer.
Alan