The Reformers knew this full well and took great pains to be faithful in their gathered worship assemblies. They read Scripture as saying, "Churches may only worship God in ways that are explicitly commanded in Scripture." Contrast this with the common evangelical reading of Scripture, i.e. "Churches can worship God in ways not explicitly condemned in Scripture". In short, the Reformed reading is, does Scripture command it?; the evangelical reading is, does Scripture condemn it?
Throughout the OT we read of Israel presenting worship to God in ways that were not explicitly condemned. Nadab and Abihu, Aaron's sons, offered 'strange fire' before the Lord and were barbecued. Yet this sacrifice offered by the boys was not explicitly condemned by God's word; rather it had not been explicitly required. Another example is that of the 'high places'. God commanded that Israel worship God in the place he appointed. Sometimes that place (Jerusalem) was pretty far away and inconvenient to get to for some Isrealites. So instead of going to temple, temple came to them in the form of the 'high places'. The Isrealites were worshipping Yahweh on these hills, but still in a manner not prescribed by Yahweh. The biblical narrative is clear in its condemnation of such practice.
Why is it important to worship God in only the way he prescribed? Lex orandi lex credendi. You are shaped not only by who you worship (Romans 1:18-32) but also by how you worship. It is clear from Scripture that the gathered worship of God is not a free for all where anything goes. Now some might raise the objection that these are all old covenant examples I've advanced, and that because we're now under grace we can relax and get out the rainbow strapped guitar and sing love songs to Jesus. But this objection is futile. The covenant may change, but Jesus Christ remains the same yesterday today and forever (Heb. 13:8). Sure, we are not under the OT law as at Sinai, but as at Sinai we must STILL approach with reverence and awe because God is STILL a consuming fire (Heb. 12:29). If we profane the Lord's Supper, we run the risk of death (1 Cor. 11:30). We must not go beyond what Scripture says when gathered for worship.
Scripture only requires three things of us: word, prayer and the sacraments. The word prayed, sung, preached, splashed, eaten and drunk; nothing else. I'm convinced that Sunday by Sunday evangelicals offer strange fire to God and burn incense on the high places in the following ways:
- By performing drama skits instead of preaching the word.
- Using grape juice for wine and wafers for bread.
- By turning sacred worship into puerile and childish entertainment, sometimes even involving puppets (I've mentioned these abominations before)!
- Praise songs that resemble more N-Sync than the Songs of Zion.
- Failure to sing any inspired texts.
- By displaying videos of anything really, just to keep the people 'engaged'.
- By permitting pictures representing members of the Trinity projected on DVD, hung on walls, or coloured in by the children in Sunday School.
- By relentless hilarity and joking from the platform (I've been guilty more than most of this).
- By extended praise times to 'enter God's presence' followed by a 15 minute epilogue. You don't enter into God's presence through a praise time.
- Celebrity culture in our meetings including boyband worship leaders and smiling DJ-esque chairmen.
- Regular failure to incorporate confession of sin in assemblies.
- Preaching only 'positive' messages.
The law of praying is the law of believing. We approach God with this laze fare attitude and then wonder why our kids don't fear the Lord or take the warning passages of Scripture with any seriousness. It's time to Reform our churches or lose the next generation. Judgement begins at the house of God and we're in danger of Jesus snuffing out our light completely.