Rom 8:6
But now we are delivered from the law, that being dead wherein we were held; that we should serve in newness of spirit, and not in the oldness of the letter.
Aquila,
I'm sure you agree that the letter of the Law states no adultery while the spirit of the Law states not to even look lustfully.
Also, the letter of the law states no killing, but the spirit of the law sates not to even hate.
So consider the letter of the law when it comes to the fourth commandment (keeping the sabbath). They (Natural Israel) were to do on work on that day.
Now, what do you think is the spirit of that same commandment?