Rome is only beginning to wake up to the damage done by the hymns of recent years long on imagery but light on theology. Some Lutherans have woken up but others refuse to believe that it matters what you sing as long as you love singing it. This is especially egregious since hymns are kind of a Lutheran thing. We sort of re-invented hymnody and congregational song and without it the Reformation may not have actually happened. The Gospel was literally sung into the hearts and minds of the faithful until that was the only thing they would settle for. When that Gospel and orthodox doctrine are no longer being sung into the hearts and minds of the faithful, something else is. And that is a problem.
No pastor wants to know the favorite hymns of the folks in the pews. Inevitably you will have somebody or more than one somebody insisting that In the Garden is not only their most favoritist hymn of all but the best one every written and it just sends goosebumps up their spine and puts tears in their eyes every time they sing it. The problem is that In the Garden probably fits a lot of their theology -- me'n'Jesus against the world, Jesus loves y'all but He loves me bestest, and nature is the place where God speaks to me more than anywhere else. Folks don't even think about what they are singing. Or maybe they do.
Even pastors have crazy hymn favorites. I have been at pastors' funerals where we sang terrible hymns because the pastors said that is what they wanted. They were not in our hymnals and did not express the faith we confess and these pastors promised to confess at confirmation and ordination, but so what? They are only hymns, right? They really do not matter. It is all up to personal preference -- what we like to sing, what speaks to our inner soul, and what makes us feel better.
Well, I am just going to say it. If we confess it in words (creed and Confessions) then we ought to be singing it in hymns. If the Scriptures teach it, then we ought to be singing it in the Church's song. Because the more we sing it, the more we believe it -- while that is true of bad theology, it is equally true of good theology! Hymns that confess have a salutary catechetical function and one that accords well with the other places where the faith is taught, learned, confessed, and witnessed. We ignore this to our peril.
Just like folks who listen to contemporary Christian music all day long will see their catholic and apostolic theology diluted and distorted by evangelicalism's focus on feelings, earthly goals, and worldly oriented pursuits, so will folks who listen to, memorize, and pray the great hymns of the faith (especially the Lutheran chorale) will find their catholic and apostolic theology strengthened, affirmed, and supported. This makes the biggest difference when trouble, trial, sorrow, and struggle come along and the Christian must rely upon the firm foundation of Christ crucified and risen for their salvation. When you have these hymns within you, they serve as a compass and anchor amid life's storms and changes.
When I was in Seminary I would visit a blind Lutheran lady in the nursing home. All she wanted of me was to read the hymn stanzas from The Lutheran Hymnal. After a few times I looked up and saw her lips moving. She was repeating them as I read them, building up her memory, strengthening her faith, and edifying her soul. Now remember, this was TLH, a hymnal that sometimes included 25 or 50 stanzas and not modern day hymnals written for the faint of heart, with 10 or less stanzas. She had already memorized them and since she could not read them, my reading of them into her ears supported their place within her heart and mind. This cannot happen with vague hymns written for emotional highs or praise choruses that say nothing a dozen times in a row or hymns that speak about everything but that which has a reference in Scripture.
Lex ordandi lex credendi applies to hymns as well. What you sing about influences what you believe. Not every hymn in Lutheran Service Book is equally weighty but every one of them is better than what most people have as their playlist from contemporary Christian music. In our Lutheran service books, a bad hymn is rare but in the CCM playlist, a good hymn is exceptional.