To me that means esstentially two things:
1. being a minister of music, ie serving with your music. Which is more than being a musician. It means letting God bring deliverance through you, sharing your gift with other musicians, being available and humble, etc
2. more specifically, it's the set of skills needed to be effective as a musician during a service. Examples:
- picking up song keys by ear
- learning new songs on the fly as you are playing them
- making the service 'flow'
- following the preacher, etc
None of the things above are needed by, say, concert pianists. They are very specific to playing in a church setting.
