Thanks for the good question. There are some articles and discussions here: (The first article touches on your specific question.)
About
II Samuel 6:5, I think it represents more of David and the others not consulting God about the
"proper order". Just like the ark riding on a
"new cart", the instrument represented David and the others doing their best to worship God according to their wisdom. I must confess that it seems strange to me that God would eventually authorize that which I think was presumptuous at that time (
II Chronicles 29:25-27; Ezra 3:10-11), but then again, God clearly does that with building the temple (
II Samuel 7:1-7). (God authorized a temple to be built, even though David's presumption prompted the topic.) In both cases, I think we see God extending some leniency or mercy for some reason, maybe the purity of David's heart (
I Kings 8:17-19). It may be that the Jews used instruments outside of temple worship, and it may be that the Jews only refrained in Babylon out of utter grief alone (
Psalm 137), but I find the absence of contrary evidence on such a presumably common and important topic to be too mystifying. In short, it's the best I can do for today to reconcile all the passages. If you have other passages or perspectives to consider, I would welcome them heartily.
The argument and idea that mechanical instruments was unique to temple worship is not original with me; however, I cannot recall exactly where I first heard it, except I am sure that I have heard it more than once. (Of course, that's no authority. I'm just saying I can't remember an earlier source at the moment, but I am sure there was at least one, probably more.) Here are a few older references, which
might prove helpful in digging up an earlier proposal:
- Harkrider, Robert, Basic Bible Doctrine, Book 2, Lessons 1-2, Impressive Image Production, Russellville, Alabama, 1987.
- Jenkins, Ferrell, The Early Church. Florida College Bookstore, Temple Terrace, FL. 1999, pp.61-66.
- Kurfees, M. C., Instrumental Music in the Worship or the Greek Verb Psallo, Gospel Advocate Company, Nashville, TN, 1975, 1911, orig.
- Earnhart, Paul, Instrumental Music, Delivered at Church of Christ in Douglass Hills, KY, November 20, 1994, http://www.wordsfitlyspoken.org/audio/earnhart/1046A - Instrumental Music.mp3.
In every case, I think you will find only an alluding or passing reference. I don't think you'll find it (i.e., the instrument being limited strictly to temple worship - or maybe temple-and-tabernacle worship) to be a central argument in any reference, simply because it is difficult to know definitively and because it is not essential, since the entire OT law and worship is removed by the cross. In a heated debate, I would probably avoid the point, simply to avoid the distraction of an opponent spearing the apparently weakest argument and assuming overall victory.
Hope this helps!