It would be against the Confessions to argue a straight abrogation of the Fourth Commandment. Many of us would say more than that.
It might be helpful to understand that aside from the blindness and rationalizing of sin that we are all prone to, but by the grace of God that some people confuse something very basic here in an attempt to justify this.
In a sense, the Old Testament "Jewish sabbath" had some differences with the Christian one. They were, are, and shall be until the end of the world the same in that God has called His creature, man to:
1) cease from his labors
2) set the day apart to prioritize worship He prescribes
3) work six days
But there were differences in the Old Testament because the ceremonial law, and the civil law of Israel was binding on many activities that occurred regularly on the Sabbath day or on certain Sabbaths. Remember, it was centered on the sacrificial system, with a Temple and a tribe, Levites set apart to administer aspects of its observance.
This before we get to the day change to commemorate our Lord's resurrection.
This is another place where reformed theology excels.
It helps us understand "all of Scripture in the context of all of Scripture." Scripture interprets Scripture. It's not a case of taking one verse out of context, without reference to context in which it was written, or interpreting an unclear passage against clear ones.
Reformed theology helps us put this together as a moral, perpetual commandment, binding on all men in all generations.
It is something God Himself instituted and patterned at Creation, explicitly gave as part of the Ten Commandments, and which our Lord followed and nowhere abrogated. He clarified it in the face of man-made additions and wrong inward motives, but in so doing He only re-affirmed its perpetuity.
[I]Post Tenebras Lux;[/I] [SIZE="2"][I] "And God shall wipe away all tears from their eyes; and there shall be no more death, neither sorrow, nor crying, neither shall there be any more pain: for the former things are passed away." - Revelation 21:4[/I][/SIZE]