Excellence is called for all of our human endeavors: "whatever you do in word or deed, do all to the glory of God" (Col.3:17). God is glorified in our creative endeavors when we give of our very best, for our best reflects most closely (though, of course, in a very faint shadow) the image of the One who in His creative acts bestowed on us that image, including the ability to create (undoubtedly the most "Godlike" attribute which a creature can possess).
Actually all creative activity glorifies God, even that which is poorly or sloppily done, for even our most slovenly effort is infinitely above any random or accidental juxtaposition of raw materials by irrational forces: intention, even of the most misguided sort, bespeaks intelligence and personality. Even the decision to give less than one's best is a divinely enabled response of inestimable wonder, a moral choice of which only God's choicest creations are capable.
But obviously the relatively closer we attain to His standards of beauty and quality and efficiency and exactitude (however many light years from perfection we inevitably remain), the truer we are to the divine spark within us. Excellence becomes Him who is of infinite excellencies!
How much more should these things be true when the creative activities in question are those directly related to the corporate worship of God by His people, when the endeavors speak explicitly and obviously of God Himself, and seek to communicate directly His special revelation and to proclaim overtly His very nature? Then, of all times, we should marshall our greatest concentration, talent, effort and consistency. Certainly a meeting with the Sovereign of the Universe deserves as much considered preparation, dignity, and attention as that important job interview, that dinner party, that joyful wedding!
Music is a gift of God specially designed and ideally suited as a vehicle for the praise and adoration of God, and God deserves the very best musical expressions to be lifted up in his honor on the lips of His dear children. The creative act in the making of music for worship in fact parallels very closely the neverending business of heaven, which is likewise musical worship (Revel. 5:9-10). "Music for worship" says it all: the end is worship, and the means is music.
But the closer a creation is to God, the greater its potential for evil and idolatry if diverted short of its divine focus (witness Lucifer). And music can all too easily become an idol if the desire for excellence in its performance becomes an end in itself. Even the word "performance" is dangerous, as it implies something presented for an audience which is less proficient in that particular field. In worship music is offered (by the congregation, or on behalf of the congregation) rather than performed; it is offered to the One who thought it all up in the first place, to the One who gave it to His creatures that they might with gratitude return it to Him. We should offer the best we can (none less than the best of the flock was demanded for sacrifice in the Old Testament); yet, as also in the Old Testament, the heart attitude of the one offering the sacrifice of praise is of far more significance and value to God than the quality of the sacrifice itself. The true end of worship music is the satisfaction and pleasure of One who graciously and gladly receives such gifts, as does the parent who cherishes the intrinsically worthless present from a child because of the expression of relationship and love inherent in that act of giving (to use C.S. Lewis' analogy).
So by all means, let us be careful to never enter into the presence of our transcendent and holy God with musical offerings which are hastily prepared or lazily executed. But let us likewise be careful to realize that all of our best preparation and execution are but widows' mites dropped into the Master's treasury, which He nonetheless welcomes and cherishes.
May we strive to offer to God our musical sacrifices of praise with excellence, and may we be transported by such means to the heavenly end of worship!