Where is the LAW stating the first day of the week must be kept holy?
Well there is the following. But we need to be sure to read before and after. There is the “spirit” of the law and the “letter” of the law. The “spirit” of the law may be a more difficult standard?
Rom 14:5 In the same way, some think one day is more holy than another day, while others think every day is alike. You should each be fully convinced that whichever day you choose is acceptable.
And you think this is something that applies to the 7th day Sabbath? Why would you think that? God has already declared THAT day as his.
There were other days that started this controversy. Ceremonial days. Should gentiles be taking part in Passover? They weren't the ones God led out of Egypt. Other days also were celebrated. At that time just as now an emperor would declare a holiday. Just as we have the 4th of July or Christmas or MLK day. Nowhere is it stated let's do away with Gods Law concerning THE Sabbath. Only God has the authority to change His Law and He changes not.