Hey, thank you very much for the kind invite
@Brother-Mike! I'm glad to help!
Perhaps the first thing I can say is that whether you wish to visit an LCMS or a WELS church, like any church, you are most welcome! I'm confident that the Pastor and the congregants would be very glad to receive you and help you in any way they can. But if you're concerned about what they believe and practice, it can be useful to drop the Pastor(s) an email, and I'm sure he'd be able to welcome you and help explain things.
Having said this, I can offer a general explanation of orthodox Lutheran faith and practice on the subject, and how it's exercised by the LCMS and the WELS.
We believe that closed Communion (as opposed to open), besides being the historical practice of the Church since the beginning until very recently, is kind, loving, honest, and true to God's Word. That is, while the Eucharist is a wonderful gift from God, given out of our Lord's great love for us to console our troubled consciences with the Gospel in a tangible way, we don't take it lightly — it's most serious. So in order to receive the Eucharist, we should rightly understand what it is, lest we receive it in unbelief and to our harm. That is, as Paul says, we are called to discern the Lord's body.
So tied to the Eucharist, there is teaching that goes with it. Namely, it requires trust in the words of Jesus. As we confess in our Small Catechism, a person is truly worthy and well prepared who has faith in these words: "Given and shed for you for the forgiveness of sins." But anyone who does not believe these words or doubts them is unworthy and unprepared, for the words "for you" require all hearts to believe.
So, with this in mind, while we can perhaps begin to see the difficulty of participating in the Eucharist in a Lutheran Church, where we confess to receive the gift of God's body and blood, and a Communion in a church body where they believe, teach, and confess that it's nothing more than a memorial meal at best, or insignificant at worst. Simply, if I receive the Eucharist in a Lutheran Church and then also in a Pentecostal Church, what am I saying about the Eucharist? What am I believing about Christ's promise? What am I communicating to the world?
Now, where it gets complicated is to what extent of doctrinal unity is required to receive the Eucharist with a clear conscience. It's in this question the LCMS and the WELS differ. WELS takes this a step further, in that they also extend this fellowship to prayer, and the reason is the same. They hold that they are to be of one mind, and so, to participate in prayer with a church body of a different confession is in their view essentially to say that it's OK to compromise on truth. That is, they question how we can confess one thing by participating in one church, and confess something else by participating in another church. While I'm sympathetic to that we are called to be united and of one mind, and to strive for true unity based on God's Word, as opposed to a false or shallow unity based on indifference, this is also what the LCMS teaches, and it's my view that the WELS is going one step too far. The church body I serve in, the ILD, is doctrinally aligned with the LCMS, so we make a distinction between prayer and the Eucharist. That is, given that the LCMS and, for example, a Baptist Church both offer up prayers to the one true God, they may pray together. However, because Baptists deny the Eucharist as understood by Lutherans, which we hold to be the Biblical teaching, we then have to draw a line and work towards unity founded on God's Word.
So, in brief, the LCMS will not forbid you from praying or worshipping with other non-Lutheran Christians, though for the sake of your own conscience and edification, like any church body, they would certainly hope that you could reach a point where you can make a home in their church and share their confession of faith.
Perhaps I can add a caveat here: If we were to go to a Roman Catholic or Eastern Orthodox service, we should absolutely not participate in prayers to Mary, saints, or angels, but only to God. And it can be good to be familiar with what kind of prayers other churches make or what kind of public confessions they make in their services. This could for example be not singing worship songs with dodgy theology, or not joining in questionable prayers or reciting statements that are unbiblical etc.
It's a good but complicated question with some very complex practical implications. But hopefully this can alleviate some of your concerns.
The peace of Christ to you!
