I'm from the churches of Christ. I, of course, believe in worshiping after the pattern in the New Testament. How would you harmonize II Chronicles 30:23 with this? This text appears to show the Israelites adding seven additional days to the Feast of Unleavened Bread with God accepting it. There is no apparent authority for them to do so.
"The sons of Israel present in Jerusalem celebrated the Feast of Unleavened Bread for seven days with great joy, and the Levites and the priests praised the LORD day after day with loud instruments to the LORD. Then Hezekiah spoke encouragingly to all the Levites who showed good insight in the things of the LORD. So they ate for the appointed seven days, sacrificing peace offerings and giving thanks to the LORD God of their fathers. Then the whole assembly decided to celebrate the feast another seven days, so they celebrated the seven days with joy. For Hezekiah king of Judah had contributed to the assembly 1,000 bulls and 7,000 sheep, and the princes had contributed to the assembly 1,000 bulls and 10,000 sheep; and a large number of priests consecrated themselves. All the assembly of Judah rejoiced, with the priests and the Levites and all the assembly that came from Israel, both the sojourners who came from the land of Israel and those living in Judah. So there was great joy in Jerusalem, because there was nothing like this in Jerusalem since the days of Solomon the son of David, king of Israel" (II Chronicles 30:21-26).
Notice that the Israelites did follow the law and kept the Feast of Unleavened Bread according to the directions God had gave. The people decided that they wanted to continue another week. They did not make this a religious requirement. It was not imposed on anyone. It was something they freely chose to do that particular year.
"Who are you to judge the servant of another? To his own master he stands or falls; and he will stand, for the Lord is able to make him stand. One person regards one day above another, another regards every day alike. Each person must be fully convinced in his own mind. He who observes the day, observes it for the Lord, and he who eats, does so for the Lord, for he gives thanks to God; and he who eats not, for the Lord he does not eat, and gives thanks to God. For not one of us lives for himself, and not one dies for himself; for if we live, we live for the Lord, or if we die, we die for the Lord; therefore whether we live or die, we are the Lord's" (Romans 14:4-8).
If you decided to spend a whole week worshiping God, there would be nothing wrong with that. God doesn't require it of you or anyone else, but if that is what you want to do, it would not be wrong.