When you begin peeking under the church's rug for the dust bunnies of worship controversy, the floodgates seem to open (and your metaphors begin to mix, apparently). It seems a mini-controversy has come about regarding John Piper and Bethlehem Baptist Church in Minneapolis. Dr. Piper invited a Christian rapper, Curtis "Voice" Allen, to rap at some of their worship services and in another part of their building after service. This, apparently, rankled some fundamentalists concerned about the impropriety of rap for worship. (By the way, Curtis Allen loves and raps about the doctrines of grace, so we're on his side, at least theologically.)
The controversy is instructive for how (and how not) to speak in the blogosphere. Allen has acquited himself quite graciously and humbly, deciding not to stoop to his attackers' ridiculous vitriole and anti-intellectualism.
But there remains another voice to be heard: the peace hippies (!!). I don't pretend that singing without instruments gets rid of all questions about music styles and preferences, but it sure does answer any questions about instruments, and, de facto, some about style. Anyone who's ever been involved with instrumental worship knows the problems that sprout up like weeds, and the silliness that comes when folks try to answer those problems. Some only want a piano. Others want the whole band (the bigger, the better). Others think wisdom would lead us somewhere to the middle.
But unless you come sit in the peace hippie circle and decide to forego instruments in worship (like the apostles...and Jesus...), you will find a great lack of any "line" to draw. That is, why piano and no guitar? What spiritual principle are we applying there? What theological or Scriptural argument informs whether we have one drum set or three ("this Sunday in worship, the Allman brothers!")? Why a little bit of drums and no thump in the trunk? Why is "Amazing Grace" okay and Allen's "Unstoppable" so damnable?
I believe it comes down to this: by surrendering her Scriptural and historical testimony on the purity of worship, the majority of the church has become enslaved to the cult of preference and personality in worship decisions. Preference because no line of right and wrong can be drawn. Personality because the strongest personality in each debate will take home the trophy (only to realize said trophy is plastic and covered with lead paint).
The days are coming when their guitars and pianos and synthesizers and bass machines will be hung on the wall of the local Applebee's and the entire church will worship in the light of Christ's face, without the shadows of the old covenant confusing us. Come, join the peace hippies; make worship, not war.
p.s. I should say that I really like instruments and don't really want them smelted down or hung on a wall. But, for the sake of unity and purity, I would prefer them outside of God's worship.