The worship band as we know it (despite the fact that music has been used for worship since the Old Testament) is a much more recent development. A church that can put up two guitarist, a bass player, a drummer and perhaps a pianist or keyboard player are deemed more cool or relevant than churches which cannot. That being said, it is important to remember worship isn’t music, but we use music to worship. We should not discount music as a tool for worship as Psalm 150 gives evidence that we should use music in worship.
The worship band members themselves provide an interesting topic for worship leaders with many points of view. The two that I have heard argued the most are: one, get the most talented regardless of spiritual maturity, perhaps being on the team will make a change in their heart, or two, we need to get believers that are passionate for the Lord to lead us in worship—which often leaves quality behind. In my experience, if there are two extremes there is often a middle ground that should be walked instead. Giving our best to the Lord is important; therefore, we need high quality and mature hearts, since we are offering up both heart and music.
As for the skill level, we should always want those that have some kind of skill or gifting in music to take part in leading, 1 Chronicles 25:7 tells us that those who led Israel in musical worship where skilled and talented. However, we should also want them to have some spiritual depth. Leadership is given to those that grace the worship stage, whether it is to play bass or to lead the actual service. In 1 Chronicles 25:8 the musicians would cast lots to decide whom would fulfill what roll. This leaves the choosing of skill and maturity up to each individual church.
When I entered into the worship-leading arena I had just barely began singing in choir, but knew I had a good voice. I did not play any instruments and I knew almost nothing about music. However, my heart was to sing for the Lord and hope that others in my youth group would join. Over the past eleven years I have learned a great deal about music, music theory (by no means am I a master) and I have learned to first play bass, then the guitar (again by no means a master of either). In addition, my understanding, passion and heart for worship have grown. I have seen that as I have learned the external tools for worship, the internal mechanics have grown as well.
The worship band and worship leader may not be the best musician in the world, but they should bring their best and reflect the best that the church has to offer. Taking a High School student, who has an untested gift and heart into the team, may or may not be a mistake. There are however, no biblical guidelines for who should be used and chosen and how they should be chosen.
The worship band and leader will, however, set the tone musically for the morning. While some will argue for larger or smaller bands, the importance is that the team is leading the congregation into worship. Each member takes part in leading the whole, making the worship band key and of high importance to the worship time. Our culture worships best and most often through music. The heart of that music is the worship band. If the band is two people, then so be it, if it’s ten then that should fit the style of that church.
 The Worship Leader’s Handbook (Tom Kraeuter on Worship) (n.p.: Emerald Books, 1999), 129.