This question begins with an unfortunate assumption; namely, that praying or singing requires certain visible motions. Praying is more than the folding of hands and the closing of eyes. Singing is more than opening the mouth and matching musical notes with one’s voice. Praying and singing are acts of worship, and worship is always primarily about what is going on inwardly, in the spirit. Jesus told the Samaritan woman at the well, “But the hour is coming, and is now here, when the true worshipers will worship the Father in spirit and truth, for the Father is seeking such people to worship him.” (John 4:23 ESV)
There is another assumption in the question, which is that no CLC member ever prays or sings at other churches. Some don’t, but perhaps others do. The question that’s really being asked is this: “Is it appropriate for members of the CLC to pray or sing at other churches?” But here, too, there is an inherent problem in the question, because synodical affiliation is not the issue. The true issue is the error that is promoted and preached at other churches. Worship is an expression of fellowship, and no one ought ever express fellowship with anything other than the truth.
Sadly, many churches promote error through their preaching and teaching, and their members express fellowship with that error through their worship at those churches. They have either been deceived by their spiritual leaders to believe what is contrary to God’s Word, or they have been deceived by their own reason that such contrary teachings aren’t important. So they attend the church of their choosing and, through their worship, express fellowship with what is not God’s truth. Throughout the Bible, in both the Old and New Testaments, God calls His people to forsake the lies of the devil and sinful men and to worship Him only in connection with the truth as it is revealed and taught in Holy Scripture.
The CLC doesn’t exist to tell people where to worship and where not to worship. The CLC exists because God has worked a love for the truth, which comes from Him, in our hearts. It is this truth that teaches us when to express fellowship, which is always and only with that truth. Where there is error, God’s truth compels us to avoid it (see Romans 16:17-18) for the sake of our own hearts and the hearts of others, which are both so easily deceived.
This “avoiding” of error should not be done as a show of superiority, but in love for the truth and in love for the eternal salvation of others. There are times (weddings, funerals, and so forth) when circumstances will find us in a church where error is being preached. At such times our silence is a witness against the error. But keeping silent isn’t the only thing we can do—we can also open our mouths, when opportunity permits, to be witnesses for the truth. After all, we aren’t saved by our love for the truth, we are saved by hearing that truth, which is the only way for anyone to be saved. This is why the devil is so intent on distorting and subverting the Bible. He knows that it is able to save souls. Well, we know that too. So Scripture exhorts us to refrain from expressing any fellowship with error, and it also exhorts us to speak the truth in love.
If you have any questions regarding what the Bible says about this issue or desire to study it further, speak with your pastor. God has placed him in the ministry to handle this Word of truth for your sake.
Frank Gantt is pastor of Zion Evangelical Lutheran Church in Atlanta, Georgia.