What Songs Belong in Church? A Concise Guide on the Issue
Most Christians would agree that some songs don’t belong in gathered worship. The harder question is the one that actually divides us: where do we draw the line? On what basis do we draw that line? For some, if a song is labeled “Christian,” it’s automatically fair game on Sunday. Others would expand the standard to include “non-Christian” songs with Christian themes. (I still remember seeing a church sing “You Raise Me Up,” by Josh Groban, and being quite shocked). For others, only a narrowly defined style or sound is acceptable. So how do we evaluate worship music wisely, without drifting into anything-goes pragmatism on one side or some sort of legalism on the other?

Are there any passages that talk about this issue directly?
This is the first question to ask when working through any issue. Regarding this issue, Colossians 3:16 is very appropriate (cf. Eph 5:19).
Let the word of Christ richly dwell within you, with all wisdom teaching and admonishing one another with psalms and hymns and spiritual songs, singing with thankfulness in your hearts to God.
Notice that the church is charged to teach and admonish one another with psalms, hymns, and spiritual songs. In other words, these are the means by which teaching and admonishing take place. So, the important application is that our church music and songs focus on correct doctrine. To put it in the negative, we are not to sing songs that are not accurate or true, nor helpful for the body of Christ.
Are there any biblical principles that we should apply to this issue?
There are a wide variety of scriptural principles that could be applied to this issue, but here are just a couple.
The God Test. Based on the first two commandments (Exod 20:3-4), I think it is highly appropriate to be reminded of the theological fact that God is not like anything else, and nothing else is to be treated like God. Thus, how we worship God should be unique from the way we refer to other things. In other words, if you could sing a song to your girlfriend AND to God, then it’s probably not appropriate.
The Meditation Test. Philippians 4:8 is clear that only the true, noble, just, lovely, etc. ought to be meditated upon. Since singing is really just forced meditation, our songs (especially our worship songs in church) need to reflect a loveliness and appropriateness about them.
The Weaker Brother Test. I think, based on passages like Romans 14, we can infer that we would never want to make another brother stumble with our music selection. Similarly, there may be music that, at a lesser level, simply annoys others in our church. If I have elderly saints worshiping in my congregation, I need to keep them in mind when thinking about music.
Are there any wisdom principles that we should apply to this issue?
Certainly, God has gifted us with the ability to observe and use sound judgment on issues as well.
Singability. Some songs are just not written to be used in congregational singing. It may sound great on the radio, but it is just difficult to sing it in a united, cohesive way. Further, some songs may be too high in key, or too fast/slow in tempo. These considerations should be evaluated in wisdom.
Tainted Music. Some songs are tainted by association. For example, there is some modern Christian music that is written by heretics. If one were to use such songs, it might lead people to other (likely heretical) songs written by them. So, this is a tricky issue and should be seriously considered.
Repetition. This is a tricky subject too because obviously, there is repetition in the psalms. But I think we need to be careful with repetition for the sake of repetition. The repetition in the psalms is not really that common, and it is always deliberate to draw our attention to something. Many of the repetitions in contemporary praise songs are simply to add filler.
Obviously, there is much more that could be said on this important issue, but I think it’s a necessary start. At the end of the day, the goal is not to make everyone sing songs you like, but to let the word of Christ dwell richly in the church. That’s why the question isn’t merely, “Do I like this?” or “Is this popular?” but, “Is this true? Is this fitting? Is this helpful for the body?”
This also means we need to avoid two ditches. On the one hand, we don’t need an anything-goes approach where a song is approved simply because it sounds spiritual (or because it was on a Christian radio station). On the other hand, we don’t need a man-made rulebook where godliness is measured by tempo, instruments (or lack thereof), or a particular decade of church history. The Bible gives us enough clarity to be discerning, and enough freedom to be charitable.