Law itself can become an idol that gets in the way of worship to God so a specific focus on law does not automatically equate to a focus on God. And if we remain in a counter-God law focus the devil loves the confusion and division it creates. I think the Pharisees demonstrate this clearly enough. What is important is to establish why a particular focus is deemed orthodox another not. Unfortunately the NT term "God's commandments" is too ambiguous and if used to isolate the 10 commandments it is done so outside of scripture as the NT doesn't make this explicit distinction. So there is a problem with terminology because if party A views it as exclusive to specific laws and party B views it as inclusive of the entire law then the two are in disagreement and cannot be reconciled. This creates a demand to use scripture that is more explicit to build your case and if not the argument will remain unreconcilable.
The point I've been trying to make is that God's commandments are also His worship decree (the first four commandments—
including the Sabbath). It is central to being a Christian to recognize and abide by the guidelines He set forth for us to worship Him.
It's not about legalism, it's about the urgency of getting it right in these last days, because it
will be a worship issue, as per Revelation. If it weren't important, we wouldn't be stressing it so much.
If you break one commandment, you break them all. The saints are those who keep the commandments of God and the faith of Jesus (Revelation 14:12).
Revelation 14:9
And the third angel followed them, saying with a loud voice, If any man
worship the beast and his image, and receive his
mark in his forehead, or in his hand,
Revelation 14:11
And the smoke of their torment ascendeth up for ever and ever: and they have no rest day nor night, who
worship the beast and his image, and whosoever receiveth the
mark of his name.
Revelation 16:2
And the first went, and poured out his vial upon the earth; and there fell a noisome and grievous sore upon the men which had the
mark of the beast, and upon them which
worshipped his image.
Revelation 19:20
And the beast was taken, and with him the false prophet that wrought miracles before him, with which he deceived them that had received the
mark of the beast, and them that
worshipped his image. These both were cast alive into a lake of fire burning with brimstone.
Revelation 20:4
And I saw thrones, and they sat upon them, and judgment was given unto them: and I saw the souls of them that were beheaded for the witness of Jesus, and for the word of God, and which had not
worshipped the beast, neither his image, neither had received his
mark upon their foreheads, or in their hands; and they lived and reigned with Christ a thousand years.