A composition professor at my college used to groan when a kid in chapel would introduce his musical offering by saying, "God gave me this song." "If God gave you that song," the prof would intone to those around him, "it wouldn’t have parallel fifths and octaves. And it would have more than four chords!"
No doubt, the "God gave me a song" thing is way overplayed (pun intended). But it does happen—in fact, for the sake of God's people, it must happen. (And incidentally, though it isn't fair to attribute to God lousy-to-mediocre music, if God inspired the awful grammar [parallel fifths and octaves] of the Book of Revelation and the small vocabulary [four chords] of the writings of John, then he may be inspiring more dull or ugly music than refined tastes care to admit.) The point is that those who make musical worship possible in the church need God's vision if worshiping God is really going to happen.
Of the many notable things King David did in his life and reign, one of the less familiar is his thorough reform of the organization and duties of the tribe of Levi. During Israel’s journey from Egypt to Canaan the Levites were responsible to transport the tabernacle, the mobile temple, but once Israel settled in their new land the Levites had kind of lost their way. One of the jobs David gave to a particular subgroup of Levites was to make music in the temple that David’s son Solomon would build. David selected three families, one from each of the three Levite clans, to constitute these worship choirs and bands forever after. The leaders of the three families were named Asaph, Heman, and Jeduthun (a.k.a. Ethan), and all of them were prophets.
We know they were prophets because they wrote Psalms (including some or all of these), and writing God-breathed, holy Scripture makes one a prophet by definition. But we also know this because they are called such in the Bible. Heman was David's seer. So was Asaph. During David's reign, other seers, Gad and Nathan, gave musical directions that came from God himself about the playing of cymbals and stringed instruments. Seers see. These worship leaders had supernatural vision.
If worship musicians don't have vision, they do something like this:
If they do have vision, they do something like this:
Or (in my opinion, submitted just so that you know that I am pro-contemporary music) they do something like this:
I met a young woman from a non-religious background who had been exposed to Christianity by her aunt. Once she got to college she connected with the Christian group on campus. As a musician, what was most appealing to her about Christianity was the abandon with which she could sing and sway to songs like The David Crowder Band's "How He Loves." Please understand that I really dig "How He Loves" as an element of a well-balanced worship diet. But this poor girl had never heard the gospel (or at least never knew that she heard it or had never been invited to do anything about it) and never knew that sleeping with her presumed Christian boyfriend was contrary to the very love of God that she loved to sing about.
Where there is no vision in worship, it is easier for this kind of thing to happen. This is why the church needs its musicians to have true vision of God, the origin of true vision from God.