If you play with perfection, you spoil it.
Let’s say you’re entrusted with the Mona Lisa for a day. Do you think you could make some additions to Leonardo da Vinci’s work that will improve it?
Or imagine, you’ve been given the perfect recipe. It was developed by a top chef in a French kitchen, and won lots of awards. It cannot be bettered. But you decide to improvise, and add some new ingredients. Is it going to taste better?
The whole point of perfection is that it cannot be bettered. It cannot be improved. All that happens when you change perfection is that you ruin it. Any additions make it worse.
This is how the book of Hebrews views New Testament worship: it’s perfect. Old covenant worship was a “shadow” and a “copy” (Heb 8:5; 10:1), and “symbolic” (Heb 9:9), but it “made nothing perfect” (Heb 7:19). But Jesus Christ, as our great high priest, has been “made perfect” (Heb 5:9), “perfection has been attained” (Heb 7:11). “The Son has been made perfect for ever” (Heb 7:28). Jesus sets up a “more perfect tent” (Heb 9:11). “By a single offering he has perfected for all time those who are being sanctified” (Heb 10:14). Old Testament believers in the hall of faith can’t be “made perfect” apart from us (Heb 11:40). Jesus is the “perfecter of our faith” (Heb 12:2). He doesn’t gather us in shadowy worship at the earthly site of Mount Sinai (Heb 12:18-21); he leads us in perfect worship at the “heavenly Jerusalem” (Heb 12:22). The book’s whole argument is that Jesus Christ has brought the perfect worship system, that replaces the old.
Therefore, it seems fair enough to conclude that maybe we shouldn’t tamper with it!
The regulative principle teaches that in worship we aren’t just to avoid unbiblical practices; we are to avoid any practices which we’re not specifically, positively told to do by Christ. Underlying this is a conviction about the perfection of what Jesus Christ, our great high priest, is doing for us in heaven. His ministry really doesn’t need our improvement. Adding a candle here, or a new ritual there might feel nice, but it’s really like me drawing on the Mona Lisa with crayon.
This is why Reformed church services are characterised by simplicity: perfection really doesn’t need our improvement.