You then need to also deal with the Scripture that talks about not judging another on the feast days or sabbaths that they observe. One man esteemeth one day above another: another esteemeth every day alike. Let every man be fully persuaded in his own mind. (Romans 1:5) Thank you.
Not to butt in, but I'm butting in : )
**Bearing in mind that Judaism doesn't have it right either (their !!!Tradition!!! is a lot of what Christ was berating the Sadducees and Pharisees about):
The Torah says to REST on the Seventh Day. I am a Sabbath keeper, and that mainly means trying to devote Saturday to being with YHWH and removing myself from the cares of everyday life, with a distinct emphasis upon the Creation... And YHWH's REST. Judaism says no travel (walking is OK) - I adhere to that pretty much - and no work - which I adhere to with less emphasis - I try to prepare for the Sabbath by creating meals for Saturday before sundown on friday. I make no appointments on Saturday, and do no work, especially work for money. But while that is REALLY important, The ox does fall in the well from time to time. But for the most part, cold-cuts or cold leftovers as much as I can, or fasting sometimes... avoiding even doing dishes, laundry, and etc... spend the day in the Word, or studying topically, with lots of prayer time, quite often with a walk into His creation with the intention of being close to Him in the beauty of the natural world. Lots of ME! time with the Father, worshiping and music, but not to the exclusion of family (if I can help myself).
It has become a time I guard jealously, and look forward to.
All that in no way interferes with going to church on Sunday, to answer one of your questions: There is no day that is unfit for worshiping YHWH - But there is ONE DAY that He requires, and it is explicitly defined. It is the Sabbath Day.
To answer another question: I don't think that the apostles and the early Church had anything to do with moving the Sabbath. In fact, it is the Roman church who lays vigorous claim to that.
A Jewish friend of mine was able to shine a little light on the New Testament custom of worshiping on the 'first day of the week'... Because of strict prohibitions against walking too far, many people could not get to the temple or synagogue on the Sabbath, so it was already customary to have worship services after dark on Sabbath, which, being YHWH's time, after dark on the Sabbath is actually the first day of the week... It was his contention that the service where Paul talked deep into the night (and the kid fell asleep and fell out the window) was actually a Saturday night, and the service probably started at dusk on Saturday.
And as a side note, he further speculates that the Christian custom of having potluck dinners after the service may derive from Judaism of that time - Since it was strictly enforced that no food preparation was possible on the Sabbath, those services on Saturday night were often potluck too, with everyone cooking something up before heading to the service...
You then need to also deal with the Scripture that talks about not judging another on the feast days or sabbaths that they observe. One man esteemeth one day above another: another esteemeth every day alike. Let every man be fully persuaded in his own mind. (Romans 1:5) Thank you.
If you would kindly read up the page from Rom 1:5 you will find the context is having to do with fasting, not the Sabbath or the holy days that YHWH ordained.
Actually, Paul didn’t speak of believers assembling on Sunday several times. The apostles preached every day, so it is not unusual at all that they would preach on a Sunday (or any other day of the week). That is simply an erroneous notion, and those passages cannot be used as proof texts for forsaking the Sabbath, which is something YHWH blessed forever.