I think that King Jeroboam of the northern kingdom of Israel must be the patron 'saint' of the modern American church. You remember king Jeroboam, right? He was the one who came before Solomon's son Rehoboam to ask that he reduce the heavy burden of labor that Solomon had forced onto the people. And after King Rehoboam denied the request, it was Jeroboam who led the rebellion of ten of the tribes of Israel, and who himself was crowned king of those tribes in the north. And Jeroboam hadn't been king very long before he started to see a potential problem for his kingdom. The fact that the temple of Yahweh was located in Jerusalem would mean that a good many of his people would still travel down to the south in order to worship as Yahweh required at His temple. He was worried that as his people traveled thus several times per year their hearts would gradually return to the southern king of Judah. So, Jeroboam came up with a plan, and this is why I say that he must be the patron 'saint' of the modern American church.
First, King Jeroboam would make the pilgrimage to the place of worship more convenient. Instead of the one temple down in Judah, now the northern king told his people that there were two new alternatives for worship much closer right there in the land of Israel. He put one of these places in Bethel and one in Dan (1 Kings 12:29). Now the people would not have to travel so far: a welcome change from the oppressive commands of old!
Second, King Jeroboam made some symbols that people could look at to focus their worship. Instead of just a place to bring sacrifices and pray, now they had some beautiful golden calves to give their worship some meaning beyond simply bringing the offerings that God required. Worshipers could focus their attention and finally feel like their god was a little closer to them. This made the god easier to manage: less spiritual, invisible, all-powerful, and holy. He became more familiar to them; they could finally understand the one that they worshiped.
Third, King Jeroboam removed the stringent requirements on who could and could not officiate temple service. Yahweh had commanded that only the Levites could serve the temple, but Jeroboam saw the oppression in that and so he let anyone who desired to do so become one of the leaders of worship (1 Kings 13:33). Gone now were all of the arguments of years gone by over who could be the special ones who serve the temple. Now anyone who wanted an inside job with little heavy lifting could sign right up. This was progress!
Fourth, King Jeroboam invented his own feast days (1 Kings 12:33). Those others that Yahweh had commanded weren't as good as the ones that he could "devise from his own heart", so he set up new ones. After all, what could possibly be wrong with inventing a new celebration of worship? It all just adds to the experience!
Finally, he removed senseless restrictions on where people could worship. Sure, he had already made the two temples at Bethel and Dan for convenience, but he also allowed the people to worship on any old high hill that they desired. Yahweh had said that this was off-limits, but the new easier-to-understand gods that Jeroboam had made didn't care one bit! If you want to worship over there on that mountain in your own way, why should anyone stop you? The new worship is all about what makes you feel good about the experience!
Note as you read the chapters concerning Jeroboam in 1 Kings that there are no stories of any other sin that the man might have committed. We are not told about adulteries, murders, covetousness, abortion, homosexuality, or any other 'low' sin that he may have been involved in. Far more destructive than any of those things in God's eyes is what this king did concerning the worship of Yahweh: how he broke from the clear instructions that God had given in order to make things more convenient and to not have to tell anyone, "No! You can't do that!" And the pronouncement that we have in the Scripture concerning all of Jeroboam's changes was that, "this thing became sin to the house of Jeroboam, so as to cut off and to destroy it from the face of the earth" (1 Kings 13:34).
Sadly, it is far too easy to see the many parallels between Jeroboam's great sins and our own in the modern American church. We try to remove every obstacle we can that might keep lost people from coming to church (even though the gathered worship is for believers and not unbelievers anyway), but in doing so, we remove a lot of what God has commanded should be in there. We are constantly about the business of reducing God down to a manageable size: something that we can comprehend and that exists only to serve us. We loathe to tell anyone "No" in worship, and let just about anyone stand behind the pulpit, teach our children in Sunday School (which is itself one of those added-on things that has become a sacred cow in today's church), lead the singing, or whatever. We invent holidays and celebrate them like we want to (when was the last time you saw a command in the Scripture to celebrate Christmas or 'easter' - named after a pagan goddess that Jeroboam was even credited as worshiping?). Our worship is all about doing what you feel is right and what makes you happy - what gives you the 'warm-fuzzies'.
God has not refused to speak on the kinds of things that He demands be a part of His worship in New Testament times. It isn't as if He only really cared about such things during the Mosaic Covenant. He has purposefully given us many instructions all throughout the New Testament epistles on how we should do church, but tragically most of these get completely ignored in favor of "what we've always done". Tradition and whim are not the determiners of what true worship should be - God is! Let's covenant more faithfully to pattern our churches and our worship on what He has said and leave "the devices of our own hearts" outside the doors.