Pick up any classical Reformed or Lutheran Protestant confession on Sunday Worship and you'll never see the "it doesn't really matter" attitude on display. See WCF 21:7f, for example.
i) I’m not Lutheran.
ii) For that matter, I don’t begin by asking myself “what’s the classical Reformed position?” on this or that issue. Rather, I begin by asking myself, “what does God command, forbid, or permit?”
iii) The “classical Reformed position” is actually rather varied. For instance, see Francis Nigel Lee’s historical overview:
iv) Over and above the “classical Reformed position,” Reformed theology has also pioneered redemptive-historical theology. Applied to the Sabbath, that lends the Sabbath a fundamentally eschatological orientation. For instance, see Richard Gaffin’s analysis:
v) I didn’t evince the “it doesn’t really matter” attitude. Whether or not it “really matters” is contingent on whether or not it really matters to God, according to his revealed will.
Antecedently speaking, it really matters that we make a good faith effort to ascertain the Lord’s revealed will. Whether or not it still matters as a result of our study is a subsequent issue.
It “really matters” that we ask the question, and direct our question at the right source to answer the question. The answer will then determine if it still matters.
“The whole attitude of "everything except Jesus-is-Lord is non-essential" is a joke and mockery of Christianity and nothing short of a sign that Protestantism on it's last legs.”
Needless to say, my post didn’t display the “everything except Jesus-is-Lord is non-essential” attitude. That’s a slanderous characterization of what I wrote.
“The classical Protestant approach is that the moral principles behind the 10 Commandments are to be a guide for Christian life, and the 4th Commandment touches upon the Sabbath day and it's basic precepts. From there it is argued that the Mosaic Sabbath being fulfilled in Christ, the "New Sabbath" is Sunday.”
What we have is an issue of theological method.
i) On the one hand, the Sabbatarian starts with the presupposition that the Sabbath is a creational ordinance. He begins with the terminus of the creation account in Gen 2:1-3. Strictly speaking, this has reference to divine rest, not human rest. A divine Sabbath.
However, that foreshadows the Mosaic injunctions concerning the Sabbath–where human rest is grounded in the divine exemplar. So the Sabbatarian interprets Gen 2:1-3 through the lens of later Pentateuchal statements. And since the Pentateuch is a literary unit, with intertextual connections, that’s a legitimate procedure.
That supplies the Sabbatarian benchmark against which other Biblical statements are measured and harmonized. And that’s a fairly strong argument.
ii) On the other hand, what I’ll loosely term the Baptist position begins with certain programmatic statements in the NT (Rom 14:5-6; Gal 4:9-11; Col 2:16-17; Heb 3:7-4:13). He views these passages as indicating a break with the status quo ante as we pass from the promissory stage to the era of fulfillment. That, too, is a legitimate procedure. That, in turn, supplies the Baptist benchmark against which other Biblical statements are measured and harmonized. And that, too, is a fairly strong argument.
These are both respectable arguments.
But there are other refinements:
i) A day of worship isn’t synonymous with a day of rest. In principle, a day of rest could be different from the day of worship.
Indeed, there’s a danger of turning Sunday into just another workday. A religious workday, bustling with religious activities instead of mundane activities.
ii) It’s meaningless to speak of a Sabbath “day,” as if we could identify a particular day in isolation. For a Sabbath day is inherently relative. Relative to a larger temporal sequence. The basic pattern is, of course, six days work followed by a day of rest.
So the fundamental unit is not the day, but the week. A cyclical sequence.
iii) Apropos (ii), even if you shift the sequence forward or backward by a day or so, you still preserve the sequence, as well as the symbolic significance of the sequence.
iv) The “1st day” or the “7th day” has no intrinsically religious calendrical significance. For what constitutes the “1st day” or the “7th day” is relative to whatever calendar you’re using. That’s a calendrical convention.
v) Apropos (iv), in the NT calendar, the 1st day is significant precisely because it stands in contrast to the status quo ante of the 7th day as the preexisting Sabbath.
But once you make Sunday the Christian Sabbath, then by shifting the entire sequence a day you thereby lose the original point of contrast. You lose the original framework which made the 1st day significant in the first place.
vi) As such, the significance of the date is something which must be assigned, not by the calendar, but by God, or by the understanding of the worshippers. If they worship on Sunday to commemorate the Resurrection, it is not the calendar alone which confers that symbolism. Rather, that’s an association which God or Christians must ascribe to their day of worship. And that’s true of symbolism generally.
Take communion bread. Communion bread is indistinguishable from any other bread. The symbolic significance of communion bread is something that Christians ascribe to the bread by situating the bread in a theological narrative.
vii) Or take Easter. Most Christians celebrate Easter. But there’s nothing special about the date. For the date of Easter is variable. What makes Easter significant is not the day on which we happen to celebrate Easter, but the event which that (variable) day commemorates.
viii) Ultimately, we can never worship God excessively. Everyday should be worshipful.
But since the church has a corporate life, we need to set aside times of public worship.
And it’s also edifying to set aside times of private worship, where we can give God our undivided attention.
“Now, you're free to say these Westminster folks didn't have the Holy Spirit and thus couldn't really understand what Scripture was saying (which is what you're almost forced to say), but you surely realize where that put's you.”
That’s another straw man. I have never taken the position that the Holy Spirit whispers the correct interpretation of Scripture in our ear.
“It's nothing short of Luther's ‘Here I stand,’ perpetuated throughout Protestant history, each time eroding away more and more of the heritage that came before it until there was truly nothing left to call Christian heritage and society.”
i) Well, I’m not interested in preserving a heritage for its own sake. What’s important is to honor God in our lives, according to his revealed will.
But, of course, papists like Nick reduce piety to playing-acting. He will dutifully play whatever role his denomination assigns to him.
ii) As far as that goes, many papists lament the loss of the Tridentine Mass. That was their heritage.