What does God's Word tell us are appropriate songs for church worship? Let's look at what two passages say about this. Where these guidelines stop is where we must then apply taste and good judgment.
"Speaking to one another with psalms, hymns, and songs from the Spirit. Sing and make music from your heart to the Lord." (Eph. 5:19)
"Let the message of Christ dwell among you richly as you teach and admonish one another with all wisdom through psalms, hymns, and songs from the Spirit, singing to God with gratitude in your hearts." (Col. 3:16)
In order to better communicate, let's separate the music in question from the lyrics. In Ephesians 5:19, the psalmist begins with a form of the word speak, which is sometimes translated sing. I prefer speak because I truly think he's talking about the lyrics of our songs, not the musical style we add to them. He then adds "to one another." This short clause is powerful. Why do we always think that worship is about us and our personal likes and dislikes? We are to speak and sing words that edify the whole body, not just ourselves or a select few.
All you who say, "We don't like hymns" or "We don't like choruses," are you really saying, "We don't like that style of music" rather than "We don't like the words"? The worship debates have often been about musical styles, incorrectly referred to as "hymns" and "choruses." But when we separate the music from the lyrics and define the three poetical forms that Paul, inspired by God, instructs us to use, then we begin to write poems that are in the style of hymns, psalms, and spiritual songs, rather than a style of music that we enjoy and to which we can worship.
Definition of the Three Scriptural Styles
First of all, let's define these three lyrical styles. In the Western context, a psalm is a poem taken from Scripture (but not necessarily word for word). Psalms are often repetitive lyrically, and have one topic or idea. These songs are generically called "choruses" today, but many of our choruses just don't fit this definition. Why? Because they're hymns.
So, let's define a hymn. Lyrically, hymns are poems that have multiple verses or strophes, with one or more ideas being presented and developed throughout the verses; they are generally deeper lyrically than a psalm. They can also contain a refrain or chorus that is repeated after each verse, and many composers use a third component called a bridge. With this definition, we begin to see that some of our "old" hymns don't fit this mold either. Why? Because they are psalms, not hymns. Hymns are still being written today, as they should be. Not all songs written before 1960 for the church are hymns, and not all songs written after that time are choruses.
Now, what is a song of the Spirit? This is the most difficult to define for Westerners. Spiritual songs tend to be spontaneous, songs that are sung only for a time to teach a biblical doctrine or emphasize a topical sermon series. As a missionary in West Africa, I have often seen the use of such songs. They may be a part of a congregation's worship for one service only, or they may last for up to a year. Longer than that, and I would identify them as a psalm or a hymn. They do not seek to build up one person, but a group. They seek to enrich or explain a biblical truth. They can, however, tell an earthly story that helps clarify a biblical doctrine.
If someone writes a song to go along with a sermon topic; if someone stands during the closing time and sings something that is tied to the sermon; or if someone sings a new, impromptu song inspired by the Holy Spirit (generally sung only that one time and generally tied to what was preached that week)—these would all qualify as songs of the Spirit.